First off don't be a douchebag. Don't be a pushover nice guy either.
You want the secret? Put yourself first. It can take a while to deprogram yourself, but you can't change your actions just to try to impress girls.
Yes, work out and get a better body. It got me dates from Tinder, but then when I opened my mouth, I was still Captain Sperg because I spent most of my weekend nights home instead of with friends.
All the dates I went on went nowhere because the articulate, funny, confident guy I was in text wasn't the same as the person the girl met.
After a month of failure, I just stopped caring. When I stopped caring, and didn't let myself fall for anyone, didn't trust anything a girl said to me on a date. Slowly, though, I started to learn and get better. I started getting nudes, getting laid, and started to have the power to walk away from even the hottest girls to the point where if I lost one, I had several others on deck.
I could comfortably kiss a girl after a date or two, get naked with her generally on date 3, depending. I don't really do that anymore because I found a girl I like and we've been in a relationship since April.
Keep in mind most girls are scared, insecure, lack confidence, and don't know what they're doing...and they are looking for a guy that's the complete opposite of that. No one can ever be that perfect someone, but girls still expect it.
You don't have to be perfect, you just have to realize that anything a woman has, be that her pussy or the validation you fantasize about her giving you, isn't going to make you any happier.
Only you can make you happier. Working out is a great start. You'll get more attention even if only marginally, hopefully to the point where you can get dates with Tinder to get some experience. Treat those dates as just experience and don't expect them to go anywhere at first.