How can I manage all of my skills on hotbars?

[FinaSel]

When I leveled Summoner and Black Mage, I didn't have much trouble managing my skills on hot bars.
I also don't have this issue with WHM.

But I am leveling Ninja now and there are so many skills and it seems like I need to use all of them very frequently.

I play on a PC.
I have 3 main hotbars I use for skills. Bottom hot bar has the basic combo attacks, plus Trick and Sneak attack and Death Blossom toward the middle. (which is very uncomfortable for me, but I can't find a better place.)
Second bar has ninjutsu, Kassatsu, Mug, Jugulate, Throwing Knives
Top bar has Assasinate, Mutilation, Internal Release, Blood for Blood

Other skills used less frequently are scattered about (Second Wind, Goad, Invigorate etc)

I use the shift key to target the second row and the Control key to target the top.

But my hands are not very big and I can't comfortably reach beyond the 4 key.
I sometimes need to use the mouse to click on a skill, which seems so inefficient.

I often sometimes can't even see the location of the mouse on my screen.

I am only level 51 now, but it's still overwhelming trying to reach every skill!

Do I need to buy one of those mouses with like 10 keys on them? (mine only has 3 extra programmable keys)

Please teach me how I can better manage my hotbars for efficiency and comfortableness.