Productivity blogger Scott H Young says that the key to getting more done is starting with the big stuff first and moving to the little stuff. He calls this approach "top-heavy":
Being top-heavy means the bulk of the work is at the start. A top-heavy joke has a long buildup for a short punch line. A top-heavy schedule emphasizes the start, leaving more space at the end.
He says you should tackle the most difficult, important, and largest jobs first and leave the rest for later. Sounds similar to the pickle jar approach: put in the big rocks first, then the pebbles, then the sand, then the water.