While it may sound silly, sloper only sessions can boost your proficiency with them a ton. Many people struggle with slopers, and they continue to struggle with them because they avoid them and don't practice them enough. Sloper only sessions, or focusing on slopers for a solid amount of your workout can give you the time needed to learn how to use these holds better and gain more experience with them.
When practicing slopers for your session, you must make sure you know how to effectively climb them. Before your session I recommend reading and reviewing:
After or while warming up, start by scouting for sloper holds and climbs. If your gym is limited but has a scrapboard or digital board with sloper holds you can also use that. Once you have a few climbs that are your flash level and below as well as on-level or project, you can start.
Goal: Climb on slopers to familiarize yourself with them while practicing principles such as: how to grip and use them, maximizing surface contact and friction, and engaging your shoulders.
Duration: On each of the routes selected, varying from flash to on-level, to maybe project.
Note that you may not be ready for using slopers in project-level grades due to not being familiar with them as you are with other hold types in your project grade. Start easy and work your way up.Make sure you are paying special attention to the techniques you need to be using (as seen in the pre-req articles) to get the most out of these holds. The goal isn't to send your hardest climb, but to familiarize yourself more with slopers.