Everyone has their own way....2 best I've done....1st is short with 2 - 3 guys - 12 progressively harder swings off the Tee - followed by 40 swings each pitched ball each in one round - quick and easy......2nd way which I liked better but takes awhile especially if too many players - 2 rounds of 100 each - stay in the box complete time unless you change bats....after 90 swings each swing that's a hit counts - if an out then another swing until you get 100....we took 2 rounds each this way...need about 150+ balls....if enough guys 1 pitches 1-2 shag and the most accomplished/successful stays back to get the balls let go by the hitter and coach the hitter on what he's seeing wrong...builds mind set, strength, repetition so you know where it's going when it hits your swing zone, muscle memory and stamina......we did this once a week on Weds .....played Tues, Wed, Thurs, then hit Friday normal BP (2 rounds 25) if no weekend tourney....Monday was a rest day......
Correction - above 90 if a miss-hit/out then you lost one on the count - some days you breezed to the 100 count - some days took 120 = by 120 or so it's all concentration....sometimes some of my best consistant pop cut in after about 70 swings - think the tiredness factor helped along with concentration build up that comes with it....at that point it's all refinement.....
Part of the secret is finding BP partners that show and are at your level of higher.......and keep the routine going every week.....