Of course you want affiliates with high commissions, but they should also have a solid reputation with high conversions and low reversal rates (you get $0 if people cancel after signing up). If they’re part of an affiliate marketplace like ShareASale or ClickBank you can see some numbers there. Companies likes Amazon/SiteGround are safe bets, otherwise do your research (or track your affiliate links so you can monitor their performance). Avoid affiliates offering huge commissions since this probably means they’re struggling to acquire/retain customers naturally. This will hurt your numbers (specifically your conversions/reversal rates).
But the biggest factor that determines how much money you will make, is joining a training program that will help you success. It is very hard to expect success right away if you are a beginner and all alone. The best program that offers you the information, help, tools and support to succeed is Wealthy Affiliates. Some Wealthy Affiliate members are already making over $8000 a month after only 6 months of being a member.