Couple of small things:
DO:
- keep pointing out something in their profile that caught your eye
- ask them a question, perhaps about something in their profile (doesn't have to be major or of a screening nature, just a question)
Dont:
- Tell them to send a message if they aren't interested (this comes across as defeatist from the start, it's almost offering them an out right off the bat)
- Tell them to email you back if they are interested (of course they will respond if they are interested)
My opinions on the matter lol, not that I'm an expert though