1. "Falling slowly" (English song, an episode of musical once, with simple and soothing tone, unkind words and beautiful melody, it would be better if a girl was in tune with you. You can search online and listen first. If you are a music lover, watch this Irish movie.
2. Forgetting (He Jie's song, with a hint of sadness, fits the atmosphere of the cafe. You are a boy. I tried. I can sing in a falling tone. It shouldn't be bad to use the guitar)
3. Brothers (Wang Leehom's cover of Lin Longxuan's song at the party is a very elegant song. Different people sing different feelings. I feel different, and the pitch is a little high, but I can sing in the coffee shop, and I should have strength. I believe you can sing your own flavor.
4. Love of Hawthorn Tree (often, you should have seen this movie, right? I think this song has a unique artistic conception in the movie. The song is not long, 2 minutes, suitable for singing in the coffee shop you mentioned. It is catchy and easy to learn.
Finally, in places like cafes or bars, generally don't sing too popular songs, because the listeners will compare it with the original songs. The effect is, of course, better after countless recorded singing and a series of post-production original singing. You have lost your own style, so try to sing a lighter and softer song that you like, give customers a good mood and let them have fun while drinking coffee.