Well, the long and short of it is, there is no quick and easy way to do it. The stronger you get, the fewer star points your enemies give you. Really, if you wanna level up, the best way to do it is to just fight enemies until they stop paying out. In other words, I'd say:
Quick- Fight powerful enemies.
Easy- Fight a lot of weaker enemies.
There's not really a very reliable combination of the two.
The best way to level up in my opinion is make Lugi wear the Excellent badge and Mario the Bonus badge (which you get at Toad Town at the badge shop ). It multiplies your Exp. by 1.2. and Coins by 1.6. I highly recommend it when figting bosses ( Example: you earn 1,000 exp. and with both badges you'll earn about 1,200 exp. ) make sure to touch the badge meter when full or else it won't work
In Super Paper Mario you can level up by 1st go to castle bleck chapter 8-4 2nd use shell shock and follow the shell [it has to be big] 3rd when it hits the enimes you will level up to 100. cool isn't it?
You have to complete the pumpworks level
You can get Beans, and an SP: Magic Window.
An alternate ending
You can only do it with Mario and Luigi. For Mario, press A. For Luigi, press B.
no
not really
noone
If either Mario or Luigi is under level 17 at the end, chakron will say something different at the end.
There are only 2 files in Mario and Luigi Bowser's Inside Story.
you have to hit the shell block.
on the map
way too easy.. just level up the bros and bowser to level 40.