Super Mega Baseball 2

For this one, start a new season (custom or standard) and win a few games by demolishing the cpu with hits and runs (don't go overboard, approximately 7-10 runs/game should do). You should start to see some of your players' "mojo" on the batter sheet go from neutral to locked-in, and then from locked-in to on fire, or jacked.
Once you're comfortable with the amount of players sporting on-fire or jacked (3-5 should suffice depending on your skill), play a home game and make sure you are in a position to win the game with a HR at the bottom of the 9th inning (must be losing or tied going into the bottom or the game will end). Once your high mojo players are up to bat, start power hitting until you hit a HR. If you get outed 3X or are in position to score with an infield hit, you can take it into extra innings (if tied) to avoid restarting the game. Lower your ego setting if necessary.

Note: I'm not sure if higher ego level coincides with faster mojo progression but I use 40 and was in position to unlock this in no time. I have not tried this in a game with less than 9 innings but feel free to give it a shot to save some time (assuming it works).

Edit: You can do this in games less than 9 innings. Set it to 1 inning if you want to save time after your players are jacked or on fire

Start a Custom Season with an all-99 team. Low ego helps too, obviously.
Set it to 1 inning per game, and give yourself at least 30 games just to be safe if you suck as much as I do at this.

Now play a few games, and as your team is 99 for all stats you should see your players' mojo rise quickly. It took me 4 games for my first four batters to all be Jacked, 6 to be On Fire, but this depends completely on how much you're willing to wallop your opponent before boredom sets in.

Once your first few players are at least Jacked, every single home game will count for this achievement, due to the 1 Inning setting. Simply play all your home games until you hit a home run(low ego, 99 team...piece of cake) and the achievement will unlock while your guy is still rounding the bases. Easy peasy.

EDIT: (I also paired this with the achievement for winning in every ballpark, as with 1-inning games you absolutely tear through them.)