Way to go! Clicking is so much fun, it's easy to get hooked.
Yes, you can absolutely toss the treats on the floor instead of always giving them from your hand. I sometimes toss them on purpose depending on what criteria I'm looking for. For instance, if I'm looking to add distance or different directions into the mix, I throw the treats in different directions. To work on a send out, I sometimes feed from my hand and back up each time the dog is heading towards the target so that he gradually has to go farther every time after he gets the treat.
There are several different opinions on when/how to add the word. I usually add it when I can predict the behavior fairly accurately, and I add the word as the dog is doing the behavior at first and then gradually back it up so that I'm saying the word before the behavior starts. You can just withhold the click/treat if he does the behavior without you giving the cue, but that frustrates some dogs, so sometimes I throw in different behaviors that the dog knows to get him paying more attention to the cue. (For example, come, sit, touch, sit, touch, down, sit, come, touch, etc and if he touches the target any time I haven't asked him to, I just ignore it.) Once the dog starts waiting for the cue, you can reward waiting by giving the cue.
Hope this helps!
Sarah and Renee - aka wild child