Depends on where on the toe it hurts...

General advice for those of sore toes:

1. Buddy tape the first 2-3 toes together
2. Find the shoes that work for your foot. Stiffer is usually better. Downturn and asymmetry in the shoe can help take some load off your big toe. Find a shoe that pulls your smaller toes toward your big toe so that all your toes are working together.
3. Learn to drop your heel lower than your toes.
   

On that last point....

Newer climbers tend to climb on the very front edge of the shoe and stay on the wall by engaging the edge of the shoe with the edge of the hold so it's like standing on a shelf. Like walking up a ladder. That's rarely the best way to use holds and becomes flat-out impossible on smaller edges.

Basically, you're pulling outward with your hands a little bit to keep from tipping off the wall backwards. The outward pull needs to get counteracted at your feet, which must be pushing inward. Make sense? A big part of good footwork is learning to use that.

Drop your heel below your toe and "smedge" aka smeary-edge with the spot under your big toe (call it 1/2 an inch behind the tip of the shoe). Imagine you're pressing inward into the wall. Gives you some advantages...

You're stretching out the back of your leg. Combined with tight core muscles, it keeps your body tense from fingertips to toes so that you're able to apply very consistent inward pressure to the wall. That inward (not downward!) force generates TONS of friction. Your amazing shoe rubber combined with inward pressure lets you stand on crap that seems utterly impossible.

From a toe happiness perspective, it also lets you work with a contact point a bit farther back from the tip of the shoe. That takes pressure off your toe by giving you a shorter lever arm between ankle and contact patch, and also gives you more power when you need to press up.