Went for a brief 30km ride this morning and found that the gear lever travel was way too much!

From neutral to 1st is normal (small amount of travel) but when going from 1st to 2nd I had to lift my foot off the peg quite a bit to engage gears. 3rd thru 5th the gear shift lever was still excessively "high". Actual gear engagement was fine i.e. positive as per normal. Going down thru the gears was also positive.
Where should I start looking?
EDIT: I'm embarrassed!

Lever was moving around the splines on the shaft, I forgot to tighten properly after cleaning behind the LHS cover. Gulp!