Ok I'll start with the Attributes... Might, Intellect, Personality, Endurance, Speed, Accuracy, and Luck. Might determines how much damage your character does, Intellect gives the Archer, Ranger, Druid, Sorcerer, and Thief classes more Spell Points, Personality gives the Monk, Paladin, Ranger, Druid, and Cleric classes more Spell Points, Endurance gives you more hit points, Speed makes your characters act/recover faster as well as provide a small armor class boost, Accuracy improves your chance to hit, and Luck... to be honest, I have not seen it do anything.
Now for the Skills... There's a lot of them so I'll have to break them up into 4 categories: Weapon, Armor, Magic, and Misc.
The Weapon skills are Sword, Axe, Spear, Mace, Staff, Bow, Dagger, and Unarmed. I can't list down every single advantage of every weapon, but I'll give what I know... Axe is slow, but does good damage, and they come in 1H and 2H versions. Spear is my personal favorite, because you can wield a spear and another weapon like a sword or dagger. Mace isn't particularly big on damage, but it can stun targets and even paralyze them if you're lucky. Bow is a skill that every single one of your characters should use, the damage isn't good but it's a free ranged attack. Dagger is fast, the damage at first doesn't look impressive but at one level (don't remember at the moment) you will be able to inflict triple damage... and it's triple damage per dagger. Unarmed... is.... something that... makes you do more damage when you're unarmed... I heard you can use it with Staff but I'm not sure about it - never played a Monk character before. Staff.. is useless.. unless you Grandmaster the Unarmed skill? I don't know, I don't remember.. O_O but yeah Sword is the worst skill, I'm not saying that because I fail with swords... but statwise, they're the worst. They don't have any ways to increase their damage except through higher Strength and/or Armsmaster skills.
Time for Armor skills... thankfully, there aren't as many Armor skills as Weapon skills. They are Dodge, Leather, Chain, Plate, and Shield. All of them are useful in some ways, but I find that Dodge and Plate are weaker than Leather and Chain... anyway, Dodge increases your armor class when you're wearing absolutely no armor, as far as I know... I've never used the skill. Leather is the lightest armor, I don't think it adds much (if any) to recovery time penalty for your character, but it doesn't add particularly much armor. The main perk for Leather is that at Grandmaster level, your skill level in Leather adds to your resistance against the Elemental damage. Chain is next in term of weight - I don't remember all of it, but it's good protection and at Grandmaster level, it doesn't really encumber you much. Plate is the heaviest armor you can get... it slows you down big time, but it really adds to your armor class. Even at Grandmaster, the recovery penalty is only halved, I think, correct me if I'm wrong. Shield determines how well your character can use a shield. It's very useful, unless your character uses two-handed weapons... unless you have three hands (or a tail?) I find it kind of hard to use a two-handed weapon as well as a shield.
Misc skills time =] There's a lot of them... so I'll try and make it quick. There is Disarm Trap, Stealing, Perception, Identify Item, Identify Monster, Alchemy, Repair Item, Armsmaster, Body Building, Meditation, Learning and... I can't remember the rest, I'll fill this on once I find my brother's MM7 manual. Anyway I'll just write about what I know. Disarm Trap is 100% invaluable to any party... unless you like traps going off in your face. At the higher levels, traps do a total buttload of damage so it can kill your casters and if you're unlucky, wipe out your whole party. I am serious when I say get this skill as soon as you can. Stealing is pretty much useless... unless you're some klepto kind of person O.O Perception is nice to have, because it allows anyone who has good enough Perception to dodge traps, find hidden stuff... it's nice, really. Identify Item is one of the most useful skills, because then you save a ton of money by not having to pay the greedy shopkeepers to ID your loot. Identify Monster isn't as useful, though it's fun to be able to find out the stats of what you're up against. Alchemy is a nice cash cow, and is good for making potions when you're in need... I recall I once saved my party from a tough situation with my druid's alchemy skills, but it's not always stuff like that happens. Repair Item is also right up there with Identify Item - if all your equipment is broken and you're stuck in the middle of a dungeon, you're good as dead. Armsmaster isn't very useful unless you can Master it... at Master level you start adding your skill level into your bonus damage. Body Building is good if you want more hit points, but that's all, I suggest putting it on your Cleric to keep him/her alive longer. Meditation is good only if you're a spellcaster, because it adds to your Spell Points. Learning is incredibly valuable, because it makes you gain experience points faster, which means you level up faster. More to come, hopefully ~