We would suggest you go to the products category which payout at least 4% or more.
Promoting low commission payout products can have a high conversion rate but it will be hard to earn a substantial amount of income.
Promoting high commission products has the opposite problem, with too low conversion rate, hence we choose the way between them.
To further research the profitability of promoting certain products, you should look for niche websites on Flippa to see their average earnings per thousand page views.
Any website that earns above $80 per 1,000 page views suggests that the products/keywords that are targeted on that website are decent earners.
It is being said that some products/keywords can be still highly profitable even if they have lower earnings per 1000 page views due to more/easier traffic potential.