I have somewhat of a piecemeal approach to Blaziken, since in Sun trying to wall him is virtually impossible. I typically lead with Tales, and Toxic it on the first turn. Then, presuming a SE or HJK to save from FB recoil, I switch in my nearly max def Cress to lure a FB and rack up poison damage. If instead he FBs and I lose Cress, I have Sawsbuck to revenge him. If not, I either sac Cress to FB to rack up recoil, or some other member of my party (who will be of least use in the coming battle) to do likewise, and then revenge with Arcanine's Extremspeed. If I need Tales (opposing weather team) then I pretty much switch to Cress the first turn instead, as saccing her to FB racks up over 2/3 recoil damage. If I'm feeling ballsy and want to predict a SD or Protect, I can bring in Sawsbuck early to OHKO it.
If I can predict the Blaziken lead, I may put Cress first to threaten it with Psychic (if nothing else on the team threatens her too much), though having my weather up afterwards and being sure all my mons will be at 100% when facing it is a pretty large incentive to simply deal with it straight off the bat, to me at least. Notably, in my main plan for it, if it does not SD then Cress can take care of it quite comfortably, though most will.
Pretty convuluted, but Blaziken gives Sun such hell that it's pretty much necessary to have quite a lot of contignecy plans for it.