It helps if you have some sort of shorthand for words and always use them. Arrows for directions etc. If you visit an ATC you will see how they write things down.
If you go through a complex airfield (Manchester) some of the ground movement directions are very difficult to remember, in this case it helps to write down what you think it will be beforehand then modify that. In somewhere like Manchester they used to route GA aircraft almost along the same route every time so a pre written note was fairly easy to do.