He's either busy or not interested
Just go along with it just say hey and go on with a normal conversation.
If you like this guy as more then a friend and he likes you its best to have him text you first, but if you don't wanna do it that way just say hey how are you
While you guys are texting say "we should totally get dinner sometime" or go to a movie or something you know he likes to do
he doesn't know what to say
just say hi or hey. then maybe whats up
Go up to her and ask her in person.
you could text him, email him or you could go up to him and say i would just like to be friends with the guts you used to ask him out or to say yes when he asked you out.
Just go and ask him. You can text him out if you know his number.
Just say Hey, what's up? Then continue the conversation and be yourself.
The same way you text anyone else. This "shy guy" is still a human being. Instead of being blunt and upfront, realise that it might take a little extra effort to coax him out of his shell. Instead of "Hey, let's go to the park", try "hey, can I come and see you? And later if you like we can go to the park".
say hi
Be yourself. Don't be afraid. Just go up to him and say, "Would you like to go out with me?" if your too shy to do that, ask one of your friends, or text time. or maybe wait until he asks you out.(: