I'd focus on prepping for the academics of primary. Learning your EPs/limits, course rules, etc. The academics can be pretty intense and the last thing you want to be doing when studying for tests or in between sims is trying to learn your EPs
Course rules, by the way, is how you get to and from the area. It's a lot harder than simply going to point Bravo and coming in from point Tango, you'll have to be coming from a specific angle/altitude/airspeed, turn to a heading, descend, call Pensacola approach, reach a point and then turn one way or another depending on the runway in use, etc.
The working areas (altitudes, frequencies, etc), course rules, OLFs (frequencies, runways, elevations, etc) is such a large part of Primary. Some of this you can learn without knowing anything about the T-6. You might not know what Point Nugget is but you know you can get to Point Waldo by flying 205. You'll know Five Lakes course rules goes to this point, then this heading, then that point, that heading/altitude, etc. I'd make sure you're good to go on that, that is a much better headstart than dropping a lot of money on flight lessons. I'm not saying it won't help, it's probably unnecessary. The people I saw struggling through Primary were not studying enough/studying ineffectively which shrank situational awareness and made everything in flight suffer.
If you truly can't fly and lack all ability, which unfortunately a few people do, a few extra lessons in a Cessna probably won't help. Like I said, it's almost always a study problem.
As you finish up your last two flights at NIFE, really try and internalize what you could've done better or what you wish you knew going into flight training. When you get to Primary, work on those areas. If you re-did NIFE, you'd obviously do a lot better. Going to Primary, in many ways, is like doing NIFE again (don't get me wrong, Primary is way more involved than NIFE, but if you know you went into flights not knowing EPs or high work procedures super well, you won't make that mistake in Primary)