Killing the Dragon.

If your jungle comes bot to gank and you kill bot laners/ get them low enough that they have to back and your mid is keeping the enemy mid in lane, you kill dragon.

If your mid comes bot to gank with your jungler and it is successful, you should pick up the 4 man dragon.

you can solo dragon at level 8 or 10 as a jungle

The Earlier you get the dragon, the better. It provides you an advantage in gold so i wouldn't get it too late in the game.

Thanks