I find the best way to tackle that is to organize the tasks and pick one. Doesn't have to be a super effective way of organizing them, just break them down into a less cluttered list and try getting something done. Sometimes picking the easiest one is a great way to just get into a working mindset. If that doesn't work, when in doubt use a randomizer. It sounds dumb, but pop all of your tasks into a random number system as numbers and away you go, you now have an order to do your stuff in. Best of luck!