Dated heavily through HS and college, got married my last semester of university and am still happily married. I have a few friends who are still in the dating game, and some who have gotten married recently as adults, so I'll try to fuse what I can:
+ Unless your goal is to hookup or just have fun, avoid dating apps. Dating apps are basically meat markets with a layer of social skills. Instead focus on engaging in activities that you really enjoy and meeting people through them - hiking, classic cinema, etc. Instead of judging purely on looks you'll have a chance to interact with possible partners and start with strong common ground. You'll also gain meaningful friendships this way which is beneficial in a lot of other ways.
+ Do focus on self improvement. Do active things (that are also enjoyable and fun), have a robust career, and seriously spend time introspecting your own personality and mind. Learn the finer points of manners, make sure to have spotless hygiene, and clean up your style.
+ Important note here - charisma, like everything else, can be studied and learned. I had terrible charisma until I spent time learning it. Ask a socially skilled confidant to (gently) critique your charisma and give you feedback. Consider taking something like improv if you do better in a classroom setting.
+ 60/40. 60% of your attention should be focused on your partner and their needs. You don't want to hog all the attention, but you also don't want to dote on them like some kind of clingy rescue animal. Given that people tend to be a little bit self biased, 60/40 tends to be a good split to keep in mind. Small gestures (filling their glass before yours, pulling chairs out for them, etc) go a very very long way.
+ Treat other people well, and treat other people personably. That is to say, treat others (whether it's a romantic partner or a random waiter) as if they are a good friend, and that you will see them quite frequently.