here are a couple of things I want you to consider trying that are going to help you with lowering your shopping campaigns costs and also scale up traffic coming from winning keywords:
1- Most of the times, you'll have a few keywords that are just going to be doing 30-50% of the volume, sometimes they would convert and sometimes the CPA would just be really high. What I suggest doing, and that's the campaign structure I want you guys to do, and this works only after spending a few thousands on that campaign, I want you to select those keywords – and mark them as negative keywords, download the excel file with all the other keywords and open up a campaign with those keywords as negative keywords – so that you end up with 2 different campaigns that are not overlapping , what you want to do next are 2 things – one , make sure your initial roas on the high volume keywords is lowered , so you'll get your CPA, and increase the roas bidding on the other , more broad, actually just the old campaign with those high volume keywords – as negative keywords by 10-20% , so you'll give the other keywords that were losing the auction a fair chance and get impressions.
That way – you'll get a lot more control over these really close , automatic campaigns and over bidding.
There's one last thing to do and that's prioritizing the campaigns – so under settings, you're going to set the high-volume keywords to medium priority and the campaign with those high-volume excluded – to high priority.
2- Make sure you copy those negative keywords when you have a large list into other shopping campaigns like when you decide to scale on Bing.
And in general when optimizing , make a rule of thumb, according to the target CPA, while taking into consideration the AOV coming from that keyword and most of all the avg cvr in the account – and optimize the search terms according to that, if you see a generic word coming back in multiple variations – make sure to exclude it by manually writing down the broad match type for that word and not just that specific search term that got there.
3- Google is going to pull a lot of keywords from the product description so Make sure you have a correct description written down that's on one hand – long enough and on the other hand – not too long, and if you see certain keywords that are causing you trouble in campaigns – make sure you remove them , so for example if you're selling a yoga pillow, and you start getting traffic from keywords like "pillows for my house" , see how you can write it in a different way, that's actually a pretty difficult example , but I think you get what I'm saying.
4- If you already have a list of negative keywords from a search campaign – copy them into the shopping campaign right from the start, make sure you also add generic keywords like "free", "refunds", "service" , "scam" etc. so you won't be getting that traffic.
5- Make a remarketing campaign on the shopping network, and make sure you exclude on all of the other campaigns this specific audience, this needs to be a high priority campaign too
6- Bid Adjust specific states and cities – when you have enough data – make sure you start bid adjusting certain cities that might bring you really good or really bad clicks.