Embrace variety: instead of solely focusing on one topic, study various topics during a single session. Jot down thoughts on a Post-it® Study Note to keep ideas close at hand and trade topics every 15 minutes or so.
Study with less stuff. Keep your space tidy and organised and only have the materials you need to keep your brain focused.
Get some sleep! The exhaustive effects of an all-nighter can affect your thinking for the next four days! In other words, get some sleep and keep your brain sharp instead of strung out.