Make sure you (after reset) only do the raindeer as high as possible then see that you have overal the highest possible x100 number so you get bonus for all. After that do all your raindeer increases (upgrades). If you have cookies to much you can buy the rest of the upgrades. Once you reach the 5x to all upgrades the game really speeds up. You'll see.
When it goes to slow to reach the next overal bonus or raindeer +100 or raindeer upgrade then I'd say reset.