This is a tough one, mainly because there aren't many guys who are really good at reading the signs of whether you want them to kiss you or not. Short of having a neon sign saying 'ok, I'm ready for you to kiss me now' you might find that you have to take the reigns and make the first move!
If you don't feel comfortable with being the one to go straight in for the kiss, there are some small things that you can do to encourage him to kiss you.
1. Sweep you're hair away from your face and over your shoulder and lean your head to expose your next, almost like you would if you wanted to tempt a vampire to bite your neck! A lot of men find kissing your neck sexy and this will put the thought into their head.
2. Lean quite close in, you could speak a little quieter so that they have to lean in to.
3. When people want to be kissed they look at their partners' lips in anticipation, so make sure that you do this, so he definitely gets the message.
4. When you are conscious that you want to kiss someone, you''ll probably find that you want to lick you lips in preparation, so don't stop yourself doing what you want to do naturally
5. Lastly, you could smooth their eyebrows down or stroke their hair to ensure that their face is facing yours...
...and if they still don't get the hint, you can always be brave at this point and use your hand to draw a line down to their chin, and pull it towards your face...if not, you will have to hope that he gets the hint!
Here is a video I found on how to prompt someone to kiss you!