When it comes to building a successful software, website or app, building it is just half of the battle. The other half is marketing it.
When looking for good affiliate programs to join, make sure the product you are promoting has a good product market fit & is here to stay for the long run.
I would also recommend working with programs that are at least 6 months old with revenue. You don't want to start working with a no code project only to have them shut down a week later wasting your time and money.