There are quite a few factors that influence the lead quality, I mentioned some already, so let's take a closer look at the most important ones, and how to utilize them in order to increase the overall quality of your leads.
1. Targeting OLDER people: This is probably the oldest trick of them all. Older people are more likely to become paying customers than younger ones. By older, I mean 30 or 40+, no need to target retirement homes residents 
- These people are more likely to have active credit cards, or some money on their accounts.
- 18 years old guys care more about beer than looking for love on a dating site for example.
- Younger people are more skilled when it comes to finding stuff on internet for free too.
But how do you target older people?
Some sources allow this directly, think Facebook or other social media. But what if the source doesn't support demographic targeting? You have to options here: 1. Utilize the creatives or 2. Target the right placements.
Creatives can help a lot, use texts like : Older people only, 30+ only, offer only good for 40+ people … for seniors … mature … you know what I mean. It's not gonna weed out the youngsters 100%, but it will definitely help. In case of dating offers for example, use images of older women that attract older males by default for example.
Targeting the proper placements can help too. When trying to target older people, you don't want to advertise on apps or sites that deal with games for kids for example. 9GAG.com probably isn't the best traffic source for this too. But NEWS sites, classic music apps, dating apps or sites … these are the placements you want to show your ads at. Think about your target audience and target sites that they are hanging out at.