The biggest thing is learn your data types, Word, Dword, Integer, Byte, Char, String ect...
Once you grasp these basic things it will help you later on. You don't know how many codes I have seen using the wrong data type of a given variable. Actually if you want some good advice just learn assembly, It would be the best language for memory editing like hacks require, plus its easier to make a hack in pure assembly than to make it in C++ or other higher level languages, Also will give knowledge to create your own inline hacks and find offsets and actually know what its doing.. Perfect language for hacks.