Here are a few general tips on rock shoes
If The Shoe Fits...
Don't buy your first pair of shoes too tight. If you can't get your foot flat in the rock shoes in the shop they don't fit - so don't buy them. New shoes will more likely stretch widthways than lengthways.
The Right Shoe For The Job
Most serious rock climbers will have more than one pair of rock shoes on the go at any time. These will principally be a soft smearing shoe, a firmer pair for edging or crack climbing and a very comfy pair for soloing and general bouldering.
On And Off
Boots for smearing should worn quite tight but not to the point of discomfort. It's worth having a very tight pair with a Velcro fastening which can be slipped off easily between your hardest routes and problems. Then have another pair which are comfortable so you can keep them on between routes or problems, these can also be used for long multi pitch routes too. On those wonderful but all too rare 'high friction, cold winter grit days' try warming your boots up under your down jacket before climbing, friction will be improved!
On The Edge
Edging boots, these are the tight ones! As tight as you can for your best pair and while they're new tick as many slate classics as you can. As the edge rounds off a bit they will be perfect for your hard leads on the volcanic rocks of North Wales and the Lakes.
Pull Your Socks Up
Wear socks! OK so that might be a fashion faux pas but if it's hot the sock will stop your shoe rotating on your foot. If it's cold they keep you warm and when climbing cracks they cut down on ankle abrasion. I honestly think in hot weather socks can improve the performance of the male foot!
Use The Machine
Have your favourite rock shoes been banned form the house? Too old, too dirty or perhaps even a little smelly? Put them in the washing machine, they will come out almost as good as new, freshly smelling and with a snug fit again.
Clean the soles of your shoes. A bit obvious maybe but by cleaning them I really mean clean them. Use a washing up brush and water at home, use spit, a rag and the heel of your hand whilst out on the crag. Rub them until they squeak and as you climb keep brushing collected dirt off the soles with your palms or the inside of your other trouser leg.
Pile 'em High
Remember you can never have too many pairs of rock shoes!