Drilling holes

It doesn't matter what size drill bit i use, it's never the right one, the hole just gets bigger n wall crumbles. I end up with several holes drilled and then trying to bang a nail in the wall n put a picture over to cover them all up. Why does it go wrong? Any help/ideas welcome
Thankyou

Right, just spoke to OH who is a proffesional!!
His advice is....if its a plaster board wall only you will need plaster board fixings. If its plaster board on a solid wall, depending on what rawl plug you need drill the hole the first (not on hammer setting) Once through the plaster board and into solid wall, then use hammer drill. Remember, for red rawl plugs, 6mm drill bit and 7mm for brown rawl plugs. If going into solid wall, you need a masionary drill bit. If you use a wood or metal drill on brick, it will get to hot which could blunt it or make a real mess of the wall. Hope this helps!

Thankyou so much, is very good of you and helps very much. There is a danger of more holes then wall before long

Lol. You could just say you were trying to knock through and make yourself a nice kitchen/diner!