Oh jeez.
First, practice unplugged. If you can get your legato technique such that notes ring out clearly even without an amp, then you're in good shape.
People always say this, but does anyone actually practice plugged in? I've played guitar for 10 years now and I can't recall ever once practicing plugged in. I always play plugged in when I'm playing with other musicians, but "practice" has always been something done unplugged.
Maybe it's just me, but this always baffles me every time it comes up.
Another thing I like to do is to take a 1h2h3h4p3p2p1 pattern and slide around the neck like so:
|-1h2h3h4p3p2p1/2h3h4h5p4p3p2/3h4h5h6p5p4p3\2h3etc...-|
Just moving around at random, again focusing on keeping it smooth and even.
I have an exercise similar to that, but
A----------1-3-2-4------------
E-------------------1-3-2-4---
B-1-3-2-4---------------------
and so on until the top, move up 1 fret, and then backwards as:
E-----------5-3-4-2-----------
B-5-3-4-2---------------------
G-------------------5-3-4-2---
And then you move up one fret again and do the top:
A----------3-5-4-6------------
E-------------------3-5-4-6---
B-3-5-4-6---------------------
And this can be done with hammer-ons and pull-offs as well. I think this is good because playing in those patterns trains your finger more than something chromatic would.
Edit: And also because it trains with string-skipping. I had originally entered the tabs wrong, so I fixed them. On the way down, you play the first, third, second, and fourth frets on the B string, then the same on the A string, then the same on the E string, then the same on the D string, then the same on the A string, then the same on the G string, then the same on the D string, then the same on the high B string, then the same on the G string, then the same on the high E string. Then you move everything up a fret and do it backwards... Probably should've checked the tab before I wrote that.