I don't know about you, but I have had many times when I am serving and can't seem to find the service box consistently, even on second serves. The problem comes from the fact that the serves felt right, like I was hitting them just the way I wanted, but they still weren't going in. When this happens, many people will "just get it in" and don't worry about doing anything with it. I have found this to be the exact opposite of the best solution. Instead of just putting it in play to start the point, look at a specific spot in the service box, say 1'x1', focus on that spot for a second or two, then toss and serve while thinking about hitting that spot. You don't need to break any sound barriers or kick it over the opponent's head or anything, just hit a solid serve that feels good. It amazed me the first time I tried that and my first serve actually hit the exact spot I had envisioned. The trend continued through my serving session. As best as I can tell, this works because the mind gets a bit confused when you stop aiming and use the whole service box as a target. The ball takes up about 1/500th (guessing) of that court area, which gives you a lot of margin for error, but it also means you get lax and don't hit with the same precise motion. I will add a note that this method likely only works with players who already have good ability to place the serve. I'm not saying that lesser servers shouldn't try it or it won't work, but it seems like if you don't know how to hit it there anyway, thinking about it won't help. However, over a period of practice like this, you should develop good serve placement. This also helps explain how some players have decent groundstrokes but impecable passing shots, and a similar mentality could improve groundstroke consistency too. Good luck and happy serving.