Here’s what works for me…..
I am currently learning a total of 4hours of material over a 4week period for dep gigs I have coming up. As @geoham says having playlist with songs on repeat really helps you get familiar.
i start just having it playing just in background for commute etc then ‘actively listening’ then pick the ‘easy wins’ and play them whilst writing short notes on structure etc if needed.
I then delve deeper into to the remaining more demanding pieces (sometimes not the ones you expect to trip you up!)
i often don’t get chance to practice with the bands before first dep gig so will finally watch their Facebook/youtube videos and ask them to send live recordings if possible so I can fine tune the songs. It’s amazing how often bands who’ve been playing a track together frequently evolve a track from the original (sometimes without really realising).
also - I’m sure I’m not the only one, but try to get comfortable playing at x1.25 speed if you can because somehow live renditions tend to be slightly faster than the original (unless your playing to a click)
^ hopefully that’s helpful to someone ^