Do an empty review of proof cards immediately after adding to prevent backlog
Proof cards are big, so you probably have a limit to new cards per day (maybe 1-5). This means if you solve a bunch of exercises on a day, you can add more cards than your daily limit. This starts to create a backlog, and one problem is that once you have a huge backlog of new cards in a deck (I've had 30-70 new cards, so with 1 new card per day, it could take 2 months to get to the card before I review it for the first time), you start to forget what the old problems were even about.
One trick to fixing this problem is to do an empty review immediately after adding the new proof card. You review the card and press "good" (without actually re-doing the proof). This means the card will show up again (as a review, rather than as a new/learning card) at the graduating interval (say, 1 month later).