One big problem I've had in the past is that I'd always been really bad at showing my affection to someone and always seemed to end up as the friend. I'm quite fine with talking to new acquaintances, but flirting just hasn't been my forte. The good thing about dating apps/sites is that the implication is already there. I find her interesting, she finds me interesting and we're both looking for something more than a friendships (whatever that is..). That hurdle has already been passed.
The first approach
The first approach is always a bit awkward and there's quite a lot riding on it. The first impression is quite often the only impression you get. If you freeze up and end up just having an awkward silence, that's probably it. In dating apps/sites the first approach is done through text and chatting, which is much more forgiving way of doing it. You can look at the other person's bio and pics and formulate something interesting and actually engaging to say. No awkward silences, you're chatting. It's not the end of the world, if you think about an answer a bit longer (as long as it'd not too long..).
First impression and showing your best side
You don't always look your best and you probably don't get to tell/show all your best traits on every approach in real life, but in dating apps you get to use your best pics and show your best side on your bio. They're something you really want to work on and I asked about my profile from bunch of people before actually starting to use them.
The first meeting
When you actually meet for the first time, you've already been talking for a while. You're just continuing your convo from your chats and I at least felt a bit more comfortable because of it. Now, just as a hint, you don't want to chat too long before asking for a date. You want to take the convo to the real world fairly quickly, but once a date is (hopefully) arranged, chat away and get to know them.
Have a good day!