How can I ensure that my text messages to a girl are not ignored? What steps can I take to resume communication with her? Also, what is the most important factor to keep in mind while texting a girl to make her feel attracted?
You can't and what this tells me along with your other post is that you have a scarcity mindset and that type of mindset does not lead to success with women.
If she ignores your text messages you do nothing, and move on to other women.
That's it. Stop wasting your time with women who aren't interested and start using your time to go find new women who are.
Guys think because they have a number from a girl that they have gotten somewhere. The truth is, women give out their numbers for many reasons and a lot of times it doesn't have anything to do with their interest level in you.
You could text this girl for the next year and she isn't going to go out with you. You could go online or out and about and meet a woman who will go out with you tomorrow. Which makes more sense and seems like a better usage of time?
Nothing you text is going to force a woman who simply isn't interested in you to become interested. It doesn't work like that. She isn't texting you back because she isn't interested. Period.