Macros: part 1

Macros, these are the things that can turn a good player into a great player. With macros, and many other things in Wow, the preperation time can determine how well you do.
For this example, I'm going to show you how to make a healing macro with a mouseover target.
To start off, type /m and hit [enter]. That opens up your macro interface. Now click New. A side window opens that lets you name the macro and choose an icon for it. Let's name it Heal (I know, not very imaginative of me, I'm a hunter, give me a break :p). And for the icon, select the ? at the top, that way, the spell's icon get used for the macro icon. If you want to, pick a different one, but I like to keep the icons the same as the original, keeps me from getting confused.
OK, once you have the name and icon done, click OK.
Now for the macro itself. For the first line:
#show or #showtooltip
#show puts the name of the macro in the tooltip when you mouseover the icon, #showtooltip puts the spell tooltip there.
Then:
/cast [target=mouseover, exists] {whatever heal you happen to want}
Ok, now what does all that mean? Here goes:
/cast-tells the game to cast the selected spell, pretty simple
[target=mouseover, exists]-tells the game to target whatever your mouse is over, it could be a characters picture, their toon, whatever. The exists is to prevent you from casting if your mouse is not over anyone.
You could also use target=target (that would cast the spell on whoever you had targetted), target={tank's name} (that would cast the spell on your tank, just make sure to spell the name correctly), or target={dumba$$ hunter that can't chain trap, but is very good at pulling hate off of the tank} (I don't think that one needs an explaination)
Last is the spell you want to cast, whatever heal you choose. And once again, I'm a hunter, the only heal I know is mend pet, and since that wont work on a WAR tank (I haven't tried it on a druid tank yet, hmmmm......) I'll let those that know healing choose that. Another thing to add is the rank, suppose you wanted to use a downgraded heal just use {heal spell}(rank x) where x is the rank you want to use.
That's all for now, next I'll go into modifiers.