Making a game plan is actually pretty smart when it comes to these things. As someone else mentioned, you basically just balance brevity with detail, while trying to create an easygoing tone. Here are a few restrictions that I unconsciously came up with that tend to make for smooth conversations where the girl doesn't lose interest. I'm no guru, but I tend to get like 3/4 of the girls I message to imessage so I think I at least have the texting part down.

And remember to think of these as restrictions that lead to better expression of your true personality, a la the 5-7-5 restriction of Haikus:

1. Write responses that give a lot of information but aren't longer than 2 lines (I use desktop. On vertical phone, 4-5 lines max)
2. Never end a text with a period. It makes for a falling tone, which can be read as overly serious or insincere
3. If you have a response as well as a follow-up question, separate them into two messages. It looks better and more spontaneous/witty
4. Not a rule, but throughout the beginning of the conversation, look for natural opportunities for ways to introduce aspects of the other person's bio. I remember one time this girl had rollerblading and Studio Ghibli as two of her interests, so I said something about how skating makes you feel like you're flying, and how I wish I had Nausicaa's glider. Stuff like that goes over really well
5. After 3-4 days of texting a person, send them your number (if they're verified) and ask them if they want to move to text
6. Lead with real life things, not consumer interests. Once they like who you actually are, they won't care if you're into anime or something, but just hold off on that stuff until you've established yourself as having a life outside your interests
7. filler "lol" to create an easygoing tone, and "LOL" when she says something funny

That's basically my "game plan." Hope this helps!