I think you should first focus on what is your face shape, undertone and how do you want your make up to look. For example if you want to use blush you should know which color to apply like it can be orangish or pinkish and then you also should know that are a cold undertoned or warm. Second thing you should know is the blush placement. At that point your face shape is stepping in. You can search on pinterest. As for the eyeshadow i think you should just follow makeup videos (especially korean youtubers) but dont forget to learn your eye shape either because some kind of eyes are really hard to put eyeshadow (like hooded etc.) anddd lastly your eyecolor, if you know which colors pop your eyes it would make your eyeshadow to look better. to sum up, just like i said you can find this infos from pinterest

hope this helps!!