Hi,

Does anyone have some suggestions on things to consider/do in order to take a good photo for a Topo?

Example, ideal locations for the sun? (Perhaps you don't want it directly behind you, as some shadows are desireable? ).  Touching up contrast and brightness etc, to maimise clarity. 

Any cunning tricks on how to get the best shot composition  etc?

It is mostly about being in the right place at the right time. A photo with good directional light that highlights the crag features is ideal but a photo doesn't have to be perfect to be useful.  Of course some crags photo much more easily than others. A wide angle lens helps a lot when you can't get back very far from the crag.