Most Helpful Guy
Damn right, do it right now. Better to be rejected than to sit in the state of what-if.
But if you're asking how, just walk up to them and say hey, I've been meaning to tell you this. I think you're really cool/cute/pretty/hot, would you like to go on a date sometime?
No matter how you spin it, do it in person. Get a date, set asap. Like the time and everything. Don't say you'll discuss it over text.