To get rid of the coldness, start qualifying women more, and be sincere - there's an article on it here:
Is Qualifying Women Really That Important?
Also, you can tell women you like them / think they're cool / that they're attractive and say it in a very bored / almost dismissive tone, and have it come off very well. Like, "Yeah, I like you, you're cool," said the way you'd say you liked some random thing that someone asked you about that you didn't care that much about but you were just saying it socially to make her feel better.
On texting for dates: the one limitation of relying on just texting to set up logistics is if you didn't make a strong first impression when you met her and you didn't get her to agree to the date then and there, sometimes you will need to get on the phone, yes. Ideally though, you want to avoid this step, as it just adds room for error into the process. Look to create strong initial impressions, connect quickly with women, then propose a date, grab a number, and text for logistics later to set up the date. Firing on all those points is your surest way to getting women out, though if you slip up somewhere along the line, sure, you can always call and take a stab at getting her out that way.