I’ve already done some posts on hunter mods (more of those to come) but macros can be just as handy for every-day play. My most spammed macro is incredibly simple:
All you have to do is have your target mob selected (or your pet will automatically attack the nearest mob) and then activate the macro. This one I put in the first slot on my right action bar and then set the hot key on that slot to a button on my mouse (this is one of those fancy mice with extra buttons on it).
It can be combined with other macro commands if you wish but I like to keep it separate for flexibility.