The answer is… You don’t! If someone doesn’t text you back, then the only thing you can control is your own desire for that person to text you back. The best bet is to move on to the next. Find something (or someone) else to do. If that person you texted wants to talk to you, they will text back, and if they don’t then you have to make the assumption that they’re not interested.
DO NOT keep texting them over and over again. That will not speed up the process, and in turn will make you look desperate. People don’t like desperate people. Desperation is a sign of weakness.
DO NOT insult them for not texting you back. All you’re doing there is making matters worse and you’re once again not only looking desperate, but you’re crossing the line into a fatal attraction type of situation.
DO NOT send sad messages looking for pity. That’s just pitiful. You don’t want someone to feel sorry for you… what you want is someone that wants you back.
What you can do is look for someone else to text. Preferably someone that does text you back. Keep yourself busy with other things or other people. You’ll come to realize that one person not texting you back is not as important as you thought.
You have to have an immense amount of self-discipline to get this done. But you’ll be surprised to find that the more you don’t expect things from people the more they’ll surprise you. So if you send out a text and they don’t text you back… MOVE ON! On to the next!!! Don’t beg. You’re worth more than that. Besides, you should never like someone more than they like you back.
Now, if you’re on the other side of the coin, and you’re the one that has to reply to somebody, read How long should you wait before texting back. That will help you decide.