The tip I have for you is to try to pick an item to make that you know is going to become popular or stay popular for a long time.
I know, I know, can’t always predict the future, but we can however make stuff that is popular right now. Heck, we can even make stuff that use to be popular, because they say that the past always repeats itself in one way or another. Also, keep in mind that as I have mentioned before here; holidays are always a good option whenever.
Like me for example; as I am writing this post the Deadpool movie is coming out, so in response to Deadpool being popular I made a few Deadpool related things that can be found here.