Sinestro pretty much out zones everyone so your aim is to be full screen. The initial problem was that when people closed the distance, Sinestro didn't have a 'footsie tool' that he could throw out and one had to respect. Now that both hits of b+1,2 are mids, people must respect him at a fairly great distance. In mid-range, you'll want to use b+1,2 and f+2,d+1,3 where you can afford to whiff the first hit, since the next two have great range.
Trait is what makes Sinestro. It helps him in the neutral game. It aids his zoning. It makes opponents stand still. It fills the gaps in between strings etc. When you end a combo end in trait whenever possible because it is easier to build it then than it is in the neutral game. You can use trait cancels to bait opponents into doing unsafe things but it has some recovery so watch out who you use it against and when. Don't do it right in someone's face.
In essence, zone and trait charge from full screen and now at mid-range you have good strings to check your opponent. Be ready to whiff punish with b+1,2 or b+1,3. Once trait is built you can afford to rush down because trait makes opponents fear pressing buttons and each trait shot is +20 on block. Optimal gameplay is to zone forever if you can afford to.
