regularly have a flick through your manual and learn something new about your DAW. even if its just one thing a week, all the little tips you learn add up and improve workflow and flexibility hugely.
I totally agree with this one. Even when I'm at work (dayjob...away from my studio) I might pull up the manual's pdf online and read through procedure I already am familiar with. Every once in a while there's a new shortcut or a different workflow that I didn't notice the first time. Then, I'm excited to get home and try it out.
A decent control surface for panning and volume, muting and soloing, can completely change your workflow. Even a cheap Korg Nanokontrol can open up all sorts of new possibilities. Having the ability to move 8 faders at once, and record the automation on the fly is pretty great.
I learned something cool about the EXS24 in Logic to get a really wide, great sounding instrument. Take a plucked string sound for example. Next, copy the track, adjust the pitch +6 or more, and then adjust the tune -6 or more (for however much you raise the pitch, make sure you lower the tune by the same amount). detune this lower by about 5 cents. High pass at around 750hz and pan hard left. Next, copy the original track again, and do the opposite - adjust the pitch -6 or more, and then adjust the tune +6 or more. Detune up at about 5 cents, high pass around 750hz, then hard pan right. Play all 3 tracks at once and your ears will thank you.
I have also taken this idea and used it similarly with other Logic instruments. Works great for clavs.