As a short document, I will only mention the stat, how it directly influences your character, and such.
HP-Health Points, Running out of these will kill you, obviously. High amounts of HP can be useful, if you also have high defense or extremely high attack power in PvP. Not really useful for traning, as buying items fills up your inventory, lessening room for enemy drops and also costing lots of money. I suggest average maybe 35-50 HP for a basic character in SMBO
FP- Flower Points, useful for using special attacks. It's good to have high amounts of this in PvP, but using it in training is obsolete (except for healing and killing bosses). I suggest approx. 25-40 FP.
Attack- Attack power. Increasing your attack by 1 will deal exactly one damage more to enemies within the damage dealing range. The damage dealing range is your attack, plus/minus ~2 damage(I may be wrong). This will result in damage to an enemy if they have 0 defense. If they have 1 defense, your damage dealt is lessened by 1. Attack can vary for each character type, as you can make your own build when you level up. You really shouldn't have lower than around 27-28 attack power, as then you'll be powerless, because Special attacks also deal more damage with higher attack.
Defense- For each point you increase, you take 1 less damage from enemies. Enemies have no damage dealing range, meaning they will always deal the same damage as long as your defense is the same. Defense can vary, but you should have somewhere between 10-24. 24 really isn't that good of a number, it's only there because that's the number where every NPC in the game can deal only 1 damage to you per hit.
Speed- Speed is actually flexible in making tough to defeat builds. It increases your block chance by approx. <0.3% per point(thanks to jdaster64 for testing this out). That is just an approximation. There may be other formulas, making the block % gain exponential, or other formulas may skew the gain. Speed really isn't a stat you want to specialize in for training, as you don't block that often. It can be useful once you reach the max level, and basically stack all the effects that increase your block chance, then you can reach around 20% block if you focus solely on about 45-50 speed overall. If you pair this up with High attack and moderate high HP, then you can really annoy enemies in PvP with the fact that you can KO them within a few hits, and although you take high damage, you block 1/5 of the time and you have high hp to save you. Each level you gain gives you 2SP, and each speed points gives you 3SP(I may have gotten them reversed... sorry). Speed really shouldn't be higher than 2 or 3, unless your focusin on a speed focus build, with around 40-50 speed.
Stache-Stache is unique, and actually can be more useful than speed in many cases. I found that the critical hit chance of stache increases slightly faster than Speed, by around 0.3-0.37% critical hit chance. Critical Hits deal 1.5x normal damage. Stache also lowers cost of everything you buy, including DE shop, Badge shop, etc... by 1% per point. Getting around 40 stache can make it useful when you want to buy Minigame items and DE stuff, especially when you know the "sweet deal" special attack, which increasing your stache by a fair amount(50%). Stache is the same with Speed in terms of suggested amount. Having 40-50 stache, plus the +4% and +2% badges for crit chance, and using sweet deal at the same time can lead to serious amounts of critical hits. I approximate around 40% crit hit chance, until sweet deal wears off.
TRAINING!!! Something people are too unwilling to do to level 60 because of the tediousness of it.
There are a few strategies and facts you should know about training.
1. Enemies won't be aggressive towards you once you are 4 levels above. (Ex. if you are level 7 then the red koopa should stop auto-attacking you)
2. Enemies in boss rooms will be aggressive no matter what your level.
3. Doing turn-based battles give about 25% more experience
4. Enemies will always do 1 damage to you, as long as your defense is higher than or equal to their attack.
5. Killing enemies gives you cards. Look up enemy attack, defense, and exp given at the card shop once registering the card you got.
Strategies:
1: Turn based battles- These are actually useful, depending on what kind of build you have. Having around 20 defense makes these builds effective. If your defense is higher than the enemies, it will sometimes negate the damage you recieve. You also gain about 25% more EXP, and multiple aggressive enemies can't attack you at the same time. 1-hit KO builds also work well, as long as you get the first strike. It is still debateable whether defense builds with Turn-based is faster training.
2. The Hit-and-Run strategy- Name subject to change. I just called it that.
This strategy is advanced, and sometimes ends up with you taking more damage than you would have just confronting the enemy normally. The basic idea is to apply your attack to a square the enemy will soon move on to, so it will take damage, then run away so the enemy cannot attack you. Try to have 1 square of distance between you and the enemy when doing this. It takes lots of practice to get this right, but if mastered, can lead to KO's of the RCC and Kamek, with only taking a couple units of damage. My description may be confusing, so I'll see if I can post some screenshots.
3. NPC avoid squares-In my opinion, this is the best strategy to use for any type of person, whether it be a level 5 or a level 50. There are certain squares that NPCs cannot go on. Such as the path with the first map when you see lakitus. Try the Hit-and-Run on this type of place. Lure the enemy, then run toward it, hit it, and go back on a zone where the enemy cannot get to. Do this quickly and killing bosses can be done at low levels. You can also use waluigi's or wario's ranged weapons, and just spam them without moving. RCC is one of the hardest bosses, other than kamek, because there are no NPC avoid squares that are useable on their maps.
Even by following these strategies, this will only lessen the cost, and death rate when training. It will probably not increase your speed at EXP gain. You can always try EXP point Plus, but it raises EXP point gain by about 5%, making it not really worth 2k WAM points. Training is training, you have to live with the tediousness:/ I hope this documentary was useful to some extent