It is important to switch up your workout frequently so your body does not get used to the same routine! There is no such thing as too much water! Your body will get rid of whatever it does not need as well as the toxins that can be harmful to your body! Make sure you do a balanced workout and switch it up often. For best results mix in cardio, resistance, and strength training a couple times a week. Also if you want to add on muscle, add in muscle training with weights as well. Never workout when you are exhausted, even if you feel like you have to. You will not get the results you are looking for during that workout because you will not be able to put the effort forth. Also, working out while exhausted can be potentially dangerous!