I guess the biggest one are as mentioned rupture uptime, but also active time seems a bit low at times.
Also I have more mastery on my non-raiding, not even fully VP geared ilvl475 rogue. (5447 Mastery vs 3989)
Also helps a lot to put up progress bars in PowerAuras or WeakAuras or something like that to easier track stuff.
I got bars up for SND, Rupture/Garrote, Envenom buff, Vendetta debuff, Shadow Blades buff.
And Icons for when Vendetta and Shadow Blades are off CD.
That way it´s easier to notice that Rupture or SND fell of, and not keep going without them for a while oblivious to the fact.
Or simply see that they are about to run out and handle it.