What mouse do you use?

A razer naga or logitech G600 would assist with increased amount of accessible keybindings as they have 12 buttons alone on the side just for your thumb to press on, less need to click on your hotbar like this.

Also, something like a razer tartarus might help with control as its a lot better ergonomically to use as your hand should wrap over device, dunno if that will help with any trembles as using a keyboard you force your hand to hover over the keys.

http://www.amazon.co.uk/Razer-Expert-Gaming-Mouse-Handed/dp/B00E8JKKPE/ref=sr_1_1?ie=UTF8&qid=1439659102&sr=8-1&keywords=razer+naga

and

http://www.amazon.co.uk/Razer-Tartarus-Expert-membrane-Gaming/dp/B00ELGHM8C/ref=sr_1_1?ie=UTF8&qid=1439659111&sr=8-1&keywords=razer+tartarus