Thank you for the responses.
Yes, I feel that my toss could absolutely use a lot of work. It's all over the place. I only really figured out where to aim the other day, which is about 6 - 10" into the court and between my head and left shoulder. Tossing higher just makes it more difficult for the moment, but it will be a very necessary adjustment it seems. I'll force myself to do it.
I go into the net very often. The head dropping thing may very well be my problem. Do you know any verbal cues for avoiding this? I mean, "don't drop your head" works just fine, but I'm wondering if there's any specific thing I should be picturing myself doing.
OK, cool, I'll try it. This was the first time recording my serve and I kind of felt that I was squatting my knees apart, while I've noticed most professionals bunch them together. I was wondering if it was a problem, and after a few times practicing with keeping the legs together to make the body "C" shape, it feels right. I'll try it in my next practice session.
Well the way to avoid dropping your head too quickly, is to tell yourself you don't need to look at where the ball lands. The reason most players drop the head during a service motion, or move their head incorrectly at all even during a groundstroke, is merely because of the urge to see where your ball lands. This instinctive feeling is hard to train which is a bit of a dilemma for many amateur/junior players since you have to call your own lines so you want to see where the ball lands in order to tell if your opponent is accurately calling the ball out/in. However, after months and years of practice, you'll know where the ball lands and you'll know if you hit the ball well enough for it land, and you will realize that watching the ball is pretty pointless. So by keeping the head still during the serve by staring at the contact point after you've hit the ball you will learn how important it is in order to maintain a good serve (or any tennis shot for that matter) as it is no coincidence that the head is typically regarded as the "heaviest" part of your body.
Go to Youtube and check out any slow motion video showing a great server (Roddick, Raonic, Federer, Janowicz, Karlovic, Isner, etc) and you'll notice they keep their head and eyes directed at the contact point as long as they can until the whole service motion is pretty much completed and they have planted their feet on the ground to prepare for the next shot.
As for your feet, I personally don't feel you should really worry too much about changing the stance especially since you are this new. As long as you are creating kinetic energy from your weight transfer process by springing up towards the ball, then that is all you need. Some players like to use their back heavily like Federer which allows him to have a very conservative ball toss in order to hit virtually any serve with a single toss. Other players, like Roddick get much of their momentum directly from the feet, and this is very noticeable as he exaggerates the feet motion. Basically, you want to have a serve that is most comfortable for you and is something you can replicate over and over in a match. This is why service motions for nearly all professional players are all relatively short and simple. You don't want to be working or thinking too hard about your serve, that is a poor way to start each point.