If you're using Jim Wendler's 5/3/1 system, don't miss this pretty thorough look at your options for variation in "Boring But Big."
Short version? There are a couple of good ways to do 5/3/1 plus 5 sets of 10 for accessory lifts.
Boring But Big
Personally I was always a fan of doing 5 x 10 as sets across (all sets and reps at the same weight), rigidly timing the rest to 60 seconds, and progessing slowly on the weight. It made the 5 x 10 into a combination of strength-endurance cardio, but also ensure you didn't mess around with extra-long rests. You just needed to get the reps done, rest until you caught your breath, and knock off the next set. It is hard, but you get it done quickly and by the end the weights all feel heavy. As a bonus it keeps you from biting off more than you can chew on the weights on the 5 x 10.