In my opinion, coming up with an interesting design is very simple. The main thing is to use a design theme that will interest the people around you. In general, in my opinion, you can make prints and interesting wall drawings to order. Why do you need to have a specific theme when you can custom paint any drawings the client requested. In my opinion, this way you can make a lot more money. For example, there are companies like DIY Splashbacks that can make custom splashback for you, which is really cool. In general, having interesting topics in advance and the ability to order your own design is very cool. In my opinion, now the most popular are the game themes and anime themes.