I feel texting has it's place, but as a general rule, calling her first demonstrates confidence. I judge each situation on it's merits though.
For example, I met this cute 20 year old girl 2 weeks ago. I established good rapport, k-closed and got her number (although her friend got pissed off me with for no reason. She convinced herself that, from her angle across the room, I was talking about her in a derogatory way. Totally false but I still had to put up with the ensuing bullshit that night).
This was on a Friday. I had a good weekend at this particular time and got a few numbers so I thought I'd experiment with a text message on the Sunday. I figured that calling on a Sunday wouldn't have been convenient (due to hangovers, visiting family, etc) I wrote in my text message the following:
"Hey, hope your friend appreciates that it was just a misunderstanding on Friday. She did her best to shoot me down though - she totally made fun of my cowboy choker! Haha! Gotta go now, I've got band practice tonight...but too tired

. Take Care. David"
My attempt here is to DHV as much as possible. I acknowledged that her friend tried to make fun of me and that this didn't faze me. Having band practice as well helped with boosting my value. I also don't ask her questions in a text message this early on. She doesn't know me well at this stage. I don't want to create that impression whereby I want her to text me back and answer my questions. It will make her think I will be sitting by the phone for answer. Best to make fun statements instead.
Anyway she responded positively and I called her the next day. No reply. Not looking good. I wait an hour. No reply. Shit! Okay, how are we going to save this one? I write:
"OMG dude, your like a mouse! Difficult to get hold of! Don't worry, your Welsh accent is cute! I'd never make fun of it!

. No worries. Anyway, you have given me an idea for the first line of a new song. It goes: "good moments pass and open the door for others". Works well with my guitar! Take care little mouse!"
She knows by now that I'm a musician in a band, so I wanted to exploit this to the fullest. So I DHV again with the guitar reference and actually show my artistic side by being inspired musically. This helps to infuse another layer of subtext (the first line of the song), make her realise she is missing out and it doesn't make me look needy. Notice the light negs also.
You may think my text message is far-fetched. But this text saved the day and she has agreed to meet up.
Texting can be a great back-up when your calls appear to be flaking.