Sometimes you'll strike a huge campaign on your 1st test, sometimes it'll be your 30th test (if you get there).
I've had a lot of campaigns over the last 2 years take off on my 30th test, that may show that affiliate marketing is becoming harder, but that's not the point. I'm wondering campaigns you've struck gold on. If you've moved onto new niches/sources share your war stories!
My Story
I started running a campaign of mine from last year on a fairly new traffic source, it was the daily deals niche. First i started daily deals big time on Facebook, and got to a point where i had hundreds of niche campaigns and it was becoming a major hassle to manage everything and i wanted to run just 1-2 big campaigns, so i started testing other kinds of traffic. This is where testing 30+ times is your best friend.
First i tested 10+ different types of traffic sources. Plenty of fish, fileserve, myyearbook, that red traffic source (redline, or bigred.. i forget the name) and lots of stuff broke even or close, but wasn't worth the effort at the time.
Then i found a source that showed promise, lots of volume, but i must have tried my top 10 best angles that I've been using on Facebook and had no luck. I tried another 15 or so angles, and still nothing. We're talking 25 different angles, 50 different landing pages, 200+ different ads, etc... Must have spent 10 hours a day for 3 weeks straight. BUT THEN i tried a new batch and the 1st angle hit big! That was that. If you give up too soon you may never know.
Goldmines you've hit?
I was once running a low volume dating campaign on FB. It was nice and steady and one day I came home from work and was sitting on my computer and started thinking "I'm going to start testing some images on the side. Just to have a back up image in case this one gets flagged or dies".
So I open up my folder with my images and I upload a batch of ads. I don't remember exactly where I found this image but I uploaded it in that batch of ads and I got them all approved. The next day I'm at work and I was overflowing with excitement and I couldn't be any happier because I was hitting $1.7k per day with a .8 ctr
That same day I quit my job and became a full-time aff marketer. I killed that image recently. It had a .2 + ctr everywhere but now it barely hits .13
I also hit a second Goldmine with that same image.. Tried it in a new country for the first time and it took me about 3 minutes to capp the offer I was testing 
Damn, how much money that 1 pic made is crazy!
I was running a campaign on TJ & a tonne of other adult sites, it worked well for 3-4 months, slowly started dieing. Then TJ released their mobile placements, I just tried it to prove myself wrong. It was never gonna work...BOOM shit went nuts ROI was 400% off the bat, other campaigns owned there too, heaps of volume. To bad it's hella saturated now.
I used to be an SEO guy. A few years ago when 'The Magic of Making Up' was very very hot. I notices that there wasn't any Dutch info on the web on 'How to get your ex back"
So I wrote (...translated an Ezine Article..) an article in Dutch and uploaded it to my datinginfo website.
A few days later I saw a Google Ad about a Dutch 'Get your ex back' book. I contacted the guy...he gave me an affiliate account and I got 50% of 69,- euro for each sale.
The translating of the article and the uploading cost me about 25 minutes.
Ofcourse...things are slower now, with a lot more competition. But those 25 minutes gave me over 50K in profit in two years.
One day I just test a new angle on FB, bye watching TV....BOOM... If you watch the ads on TV or just tv show, sports,....this is it 
Riches in Niches.....
Was testing an angle for a while that didn't work, but I changed my ad copy to insult the user and it helped drive conv. rate up drastically (surprisingly).
if your campaign was steadily doing well and then suddenly drops off, try pausing it entirely for a few days and starting fresh. some networks will even give you a new id to run it on if it starts to drop hard.
I've been running ads SOLELY on Facebook since last year. It helped me to break my first $10,000 net profit per month, however, I couldn't scale on it and FB is just a biatch (as you all know)... I knew the fact that it would be a struggle to keep on sticking to FB despite the fact that it has good money to be made. Not until 2 months back, where I stopped running ads on Facebook - and try to look for new traffic sources.... and that's when my campaign hit the next level, and ultimately, my first 6-figures month.
My goldmine? As simple as a change of traffic source. 
Traffic source changes have to be the #1 variable to hitting goldmines. Whether its trying new campaigns on these sources or porting over profitable campaigns!
I was doing ok of FB targeting a specific demographic group with some additional TIGHT restrictions/qualifications. Nice ROI but not that much volume.
One day I was like "why not duplicate it and remove those restrictions but just go broad and target that whole general demo range" -- that really opened up the Volume and ROI didn't drop much if any.
Did a Valueclick buy for 25k test on a campaign. I was getting a $40 cpa.
Day 1 of the campaign my cpa for the display buy was coming in at $180 and slowly dropped down to $22 over 2 weeks.
Ran 1200-1300 sales a day for 4-5 months. 
One thing I can tell you is as long as I've been in this business. I keep hitting new peaks and when they're happening I usually say things can never get this good again.
And they always get better.
I have 5-10 good stories for this I'll share over to time.
Pandora's Box (Vin di Carlo) on self serve (exo, tj, etc) and then direct buys. Early 2011. 1/2 Mil profit.
I vote to sticky this post to let it grow and have the new members read through to get the highs and lows of this business.
When I had my adnetwork we had so much on our plate that we didn't implement the mailings for a while even though we had millions of emails.
The day we plugged it , it added a 70k$/month stream to our PROFIT.. duh!
Never under-estimated email since then obviously! hehe 
Mehdi
Bought a site template + script + "make monies online" method in 2008 on DP for $39, modified it very slightly.
Still makes ~$1500/month, highest DAY was last year where it pulled $22k randomly (followed by several $8-12k days). I know this sounds like BS but it's not. Total earnings are over a million in the past four years, almost all profit.
$39 to a million, that's some ROI. Did you ever message that DP guy to say thanks? 
The first affiliate goldmine I ranked was doing content locking on wrestling pay per view
. It was HUGE $$$
Started targeting a product URL on PPV three weeks ago, hoping to make an extra $50-$100 per day
I have made $800 to $1k on it every single day since
Enjoyed reading all posts in this topic... thanks to all!
sick thread! bump for new stories
This was mid-2013. Promoting a campaign for eye surgery (so you don't have to wear glasses anymore), was a very long form, but people could win eye surgery worth 1500 euro if they'd apply. I didn't expect much of it, but tried it anyway. Promoted it on FB & used some crazy images that have been used for IQ quizzes as well where your eyes/brains would play tricks on you, created a prelander with questions related to eye surgery, age, health condition, ... The offer paid $20 / lead, first day I spent $200, made $2000. Scaled up in the following days and got it up to $10k / day revenue with around 800% ROI. 2 weeks later I got a call from the advertiser saying the call center couldn't handle the amount of leads and it went downhill from there. Was a pretty awesome time, especially because I didn't expect it to do well.
Still huge potential in that medical area if you're good at doing biz dev and can create the entire flow for certain parties (networks, are you reading?)
My experience in IM is a bit different. I focus primarily on the eBay Partner Network and building thin content sites. Although my background professionally is in paid search, I made the leap into full time affiliate marketing with the intention to focus on SEO (albeit at the time it was better intentions and morphed into thin site seo
). I always say I'm going to start doing CPA and then I get sucked back into building more sites.
My first "goldmine" happened shortly after I left my job in 2009. Over the holidays I always run some Adwords & Bing Ads traffic to my sites (basically just product feeds for Bing and a little beefed up landing pages for Adwords) for the hot toys/gifts of the year. That year I launched my campaign on Black Friday and left for vacation to Paris. Little did I know, I had a runaway hit with "Zhu Zhu Pets" and cleared 10k in just a few days. I was way too nervous to scale at the time so I kept it at that and was thrilled.
In 2011 the same thing happened when I was on vacation in Costa Rica (see a trend??). Leappads were the hot item and I hit my highest day up until then at $1800 for the day. That holiday I cleared about $40k in 3 weeks.
This was under EPN's old QCP pricing structure which paid out per click. This October, EPN went back to a % of revenue model with a 24 hour cookie for bids to be initiated in. Under the new structure, new users or infrequent buyers are paid a 200% bonus on earnings. So what did I do when PS4 sold out in early Nov (way before my usual launch date of Black Friday)? You guessed it
During the holiday season this year, I had my highest day ever with $25k in earnings (on about $4k in spend). I cleared $350k in 6 weeks this year. So yeah, that's my real goldmine 
Started off w/ dating on POF a few years ago.
I was running True.com and making about $150 a day profit; it was virtually on autopilot for months. As a college kid, making about $1,000 a week, I was in a good spot.
I split tested a few offers, with little luck. One day I threw in another split test overnight. $320 spend, $1,100 revenue. This campaign went on for a while.
It was then I realized that 1) there's real money to be made on the internet and 2) the only way to generate income is not to be employed by a company reporting to a boss.
Good luck!
1-2 goldmines every few years alone is enough to make affiliate marketing a very healthy full time job