I can also recommend keybind spells. It can make the difference in situations where it is required to act correctly in 1-2sec. The normal human reaction time is ~0,3sec, if your tired cause it's the third try on the last boss after hours of raiding, then the reaction time is >1sec. If you use the clicking way, it's maybe too late. Your missing 12 casts aren't the problem at all ;)
Myself, i use the keys RDFG for walk, and 17 other keys (inclusive 6 on mouse and ctrl combos) for bindings, all around these walk-keys. And as mentioned, if there are more chars, use similar spells on the same key on every char (i.e. CC skills, heal/selfheal etc.).
So far