If you are just using a dialectic material for the liquid then some sphere particals released from a hidden duplicate of the faces around the inside of the glass at a very low rate would not be a bad start. if you make it so they have to collide with the glass but have no bounce and a lot of friction, some should even stick to the sides in a realistic matter. As for the ones on the edge of the liquid surface/glass border, a circular goal object should work just fine. If that doesn't make any sense, then yes, you should look at some tutorials.