1. Focus on upgrading your Pow (responsible for your total damage value), and later on make-up for your HP value collecting Woo Beans from weak enemies (shapeas and beans) around the Beanbean Castle town. Alternatively, you may upgrade your Stache points which is useful in dealing critical/lucky hits to enemies as well as handing you the extra discounts when buying, and mark-ups when selling item/Gears.
2. BP is insignificant to mario too. Later on in the game, you'll earn the Soulful Bros. Equipment (rewarded by Hermie, when you give him the starfish as a replacement to the starbean - note that you must have the golden hammer to reach the secret area within Gwarhar Lagoon) which replenishes the cost of used BP whenever you achieved an Excellent performance in any of the "Bros. Attack". And since Mario's Swing Bros. is probably the easiest one to perform with an excellent rating and relatively high total damage, you'd probably equip this one to him -- making your BP value insignificant.
3. Speed of luigi isn't important too. Later in the game, you'll earn a costume for Luigi called Anuboo Jeans (which can be earned as an item reward from enemies in the Teehee Valley). This gear allows Luigi to take a turn right before mario. Since Mario always gets to take his turn first (with almost every enemy in the game), there wouldn't be a need to waste your bonus stat point on his Speed. To boot, it is pretty durable and with high stats too (very much similar to Mario's Iron Pants).
4. Collect every chuckle bean you see. This may become tiring in the game, especially when having to do the dunk every single time. But not only do you earn Chuckle Beans to brew in Starbeans Cafe for boosts in the speed stat, the game also records the total number of Hollow beans you have unearthed and rewards you with useful Items and gear too when you visit the Accomplishment Store in Beanbean Castle town.
5. Earn Bros. Rock Early in the game. As soon as Beanbean Castle town gets restored (when NPCs become available), you can speak with one of the townsfolk about unearthing rare gems lying around the kingdom. When you accept this quest, you should pound mario to become the small Mario and roam the area. He'll hint you with an ="!" if something suspicious is lying around nearby, and changes to an erractic "!" when you hit the exact location. Simply shift back to normal size, pick the luigi dunk action, and pop-out from that specific location to earn the gem. There will be 10 gems to look for within the kingdom, all lying around the castle town area. This equipment is very useful and will last until you get to the latter parts of the game (more useful than the sold Items on the stores even until you get to Joke's End).
6. Open your mini-map to find relative hints what to do next and where to find what ever it is that you are suppose to look for. Additionally, you may adjust the size of the map that you are seeing. If you spend time closely inspecting the areas of a dungeon, you'll see hints of special/hidden rooms which usually shows a connecting way/bridge going there.
7. Brew the different blends in Starbeans Cafe. Each time you brew a new blend, the professor (who owns the cafe) usually pays a visit and will ask for a sip of the new blend. In return, he usually rewards you a useful accessory in the game. To name a few, he'll give you the specs to see hidden blocks, An accessory that doubles your damage, the excite spring (make you float longer mid-air when dodging), and upon completing all the different blends, he'll give you the "Gameboy Horror SP" which grants you the rare item drop from defeating enemies every single time.
8. All enemies (except bosses) usually have 2 attack patterns. Each of which always has an identifier which can help you time your dodge or counter attack. Not that its easy (especially with casual gamers), but it helps a lot when you get to anticipate what is coming.
9. Take time to practice performing Bros. Attack as they would tend to be the most common attack option for both your characters later on in the game. To practice, just press the the "Practice Button" at the touchscreen part of the console whenever you engage an enemy. You may repeat this infinitely without the need to worry about your BP.
10. Take time to set records in the different mini-games in the game. Mini-games usually reward you with a special kind of bean that can be used in the Starbeans Cafe. Nothing can go wrong playing these simple games as they are fun to play, easy to win, and rewarding to boot.
11. The Barrel Game (originally played in the S.S. Chuckola to earn membership) gets transferred to the Arcade shop in Little Fungitown when the ship sinks at the ocean. Similar to other games, you may earn Hee Beans from beating records in the mini-games.
12. Always check out for the green tunnels. Whenever you see a green tunnel in the game, regardless if you need to pass through it or not, always make sure that you at least go inside it. This will remember the "warp spot" throughout the game for later use. For instance, during the latter part of the game, you'll have to go all the way back to Hoohoo Village to seek for Blablanadon's help fly you to Bowser's Floating Castle. If you happen to not have checked out the warp zone within the village, you'll have to walk all the way back there. Same goes for trying to access and acquire rewards in the Stardust Fields Jump-rope game.
13. Take the time upgrading your stats and unlocking content (for better Gears) before dealing with Bowletta in last boss battle. Similar to any Super mario franchise, the last boss always tends to be hard to defeat and always takes long to do so. You'd need a number of max mushrooms, max nuts, and super 1-ups too. If you happen to have earned the last reward item on Starbean Cafe (Gameboy Horror SP), you may easily farm for these Items by tackling enemies on Joke's End and Bowser's Castle in an alternate manner (so that they will respawn). This will help you collect these rare replenishing items, and level-up as well. (Make sure that who ever wears the Gameboy Horror SP deals the finishing blow to earn the rare item).
14. You may also buy a package of the Max Replenishing Items on Hoohoo Village. The guy near Blablanadon who wishes to buy his mom a present will try to sell you a package that is priced 750 coins for the 3 items -- which is pretty much a bargain nonetheless. Buy as many as you can since you wont have any more use for the coins when you reach this far in the game.