A lot of C++ code uses syntactical conventions for marking up member variables. Common examples include
I almost never use prefixes in front of my variable names. If you're using a decent enough IDE you should be able to refactor and find references easily. I use very clear names and am not afraid of having long variable names. I've never had trouble with scope either with this philosophy.
The only time I use a prefix would be on the signature line. I'll prefix parameters to a method with _ so I can program defensively around them.