All you need is a naga mouse (or similar gaming mouse with 3rd party macro set up)
The in game macro doesn't work past one decimal, meaning your GCD of 2.44 needs to be waited for 2.5 to work...bad stuff.
What you then want to do is make a few macros (most software lets you record actions so no programming needed, and its actually more user friendly than the in game macro, while being way more efficient)
Whatever class you are, im sure you notice you use some skills in a rotation, other situational.
The main thing you are going to have issues with is the fact that you need lots of stuff bound to your keyboard and many button on the keyboard are not viable for constant use. You are not going to want the default 6,7,8,9,0,-,= keys on your hotbar to remain that way and attempt to finger press them.
So you are going to need to go into keybinds and figure out what keys other than wasd you don't need and assign hotbar spots to them. Some even go as far as only using W to move forward and none of the ASD or QE strafe (its better to mouse turn)
So you make macros for your extra mouse buttons, and can remove those skills from your hotbar (or keep them to watch) and place other situational skills on your `,1,2,3,4,5 with the ones you use most often or time is the essence type skills to the buttons you can hit the fastest and easiest.
Now comes to rare use stuff. Food, potions, pets, strange skills or buffs. These you can set up away from your main cluster and mose over to click them. This will allow you to use just about every skill without having to dislocate a finger or create a 90 button ps3 game pad.
Some tips on keeping a clean screen. You can click the hot bar arrows on your primary hotbar, scroll back to like bar 5-7 and place combo skills or rotation skills there, go into keybind and rebind every slot with a skills to somewhere on your keyboard if you are going to macro off your mouse use like number pad binds and set that in your mouse macro, you wont even have to be on this hotbar and now those skills can be out of your way. (I do recommend placing combo and rotation skills somewhere seen for a bit as you tweak your macro so you can see them being used and cool downs ect)
Now if you did all of this...your staring now at a foreign screen whith a completely changed combat mechanic...its going to take some getting use to...you might want to rebind stuff after a bit of play...you might want to move stuff... this stuff takes PC games a bit of time to settle into a keybind/macro/HUD layout that feels right...you will find it though.
Once you get it right youll never go back...will fit you like a glove, your DPS will drastically improve if your macros are set to the correct GCD, and you wont have to ignore skills you cant use (you should never ignore skills).