The absolute best thing you can do to your tranny is change your fluid with the ORIGINAL EQUIPMENT tranny fluid religiously.
In addition to that, you can buy a heavy duty tranny cooler and just use it to replace your stock tranny cooler, or plumb it in to work with your stock one.
Some people on the board have done an inline filter tranny kit which flters even more particulates than your stock filter does and uses just a regular engine oil filter! Contact Aldive for info on this..
Lastly, you can have a shift kit installed in your tranny which will firm up your shifts a bit, or you can go the electronic route by geting a multipurpose performance chip with this feature, or by getting a standalone electronic tranny shift module. Contact Alec for more info on this.
Hope this helps.