Probably more of the same but here goes. Tire clearance is an obvious but work out what the maximum actual width of the tire on your rim (usually someone has the data), for example I ran 40mm terra speeds on a 19inch internal width rim which came out to 39mm at pressure which was within manufacturer spec.
The other consideration is gearing. Depending on the gravel country you are in you might want to have a play with your low end gearing. I recently completed the Seven UCI gravel race that had about 3200m of climbing in 125k and only had a one to one small gear. (I had 50/34 crank and 11/34 cassette) I made it but reckon some less a little easier would have been nice to keep the cadence up as the day went on. Depending on your drive train this is pretty easy to modify.
The only other thing is possibly a little frame protection depending on how precious you are on the bike. I picked up a significant rock at one point which hit and chipped my crank, not sure the frame wrap protection I had would have helped but it does cut down the little bits hitting the downtube and seat tube.