Put new strings on a few days before. Stretch them out to ensure stable tuning, and be sure to bring extras. Avoid doing this the day before, as the new strings might still be settling and may give you tuning issues.

Make sure your instrument is set up properly. Set intonation, make sure tone and volume controls, etc. are all working.

Make sure your amplification, effects, DI box, etc. are all in working order, and that you bring extra patch cords, picks, speaker cable, etc.

Have a variety of tonal options at your disposal. If you have different guitars, different amps, different effects, etc., sometimes that magical combination is discovered in the studio.

Note: I have a variety of guitars for a variety of tonal options (Telecaster, Les Paul, ESP, Rickenbacker, semi-hollow and hollowbody electrics, etc) that may be borrowed, along with extra patch cables, DI boxes, etc.