Drink Enough Water
First of all, calculate for a week how many glasses of water are you having on average on daily basis. Try to identify it to particular number within one week. Now set a target to drink at least 2 litres of water during winter and 3 - 4 litres of water in summer.
Every glass of water needs to be tracked for initial 2 weeks to give you estimation of daily water intake. If you are able to follow this for 1 month, then you should be able to follow this for your entire life.