Keeping needs to be kept simple but one thing is that it does not come naturally, you can naturally become a blocker/catcher but a wicket keeper is more than that in my view.
Firstly you need to be confident in that you will mainly be the vocal point of the side, this does not mean a mouthy so & so but supporting, encouraging and done times being totally honest with how someone is bowling etc. confident to tell the skipper what your seeing and what ideas etc
Stay low and take the ball on the up. When standing back you want to taking stock delivery waist height to reduce stress on knees, back etc. when up its late and on the up.
Relax and let the ball cone to you never snatch.
Don't best yourself up when you drop them or miss them it will happen and its part and parcel. Mainly enjoy it though.