Stats are all gained through FEP or Food Event Points which are acquired by eating different foods. Each food gives a certain amount of FEP. the total FEP required to fill the bar is equal to your highest stat (i.e. your str is 20 and all of your other stats are below 20. It takes 20 FEP to get any of your stats up.) Different foods can give different amounts of FEP. FEP does not rollover (If you only need 2 FEP to fill the bar and you eat something that gives 10 FEP, the bar will still start over at 0) When the bar is filled, you may receive any of the stats that are currently in that FEP bar. The more of a certain stat you have in the bar, the higher chance that stat will go up, but it isn't guaranteed (If your FEP bar holds 13 FEP and you have 12 str and 1 agi, you might gain an agi instead of str, though the odds of getting the str are much higher.) Each completion of the FEP bar rewards only a single stat.
Str: Affects combat damage, destroying objects, and smithing.
Acquired by eating most boar/bear meat/sausages.
Int: Affects the combat skill Opportunity Knocks. As far as I know, does very little else.
Acquired by eating Cooked Fox Meat, Fox-based sausages, and fish.
Agi: Affects certain combat skills such as sidestep. Also affects travel weariness accumulated from quick-traveling.
Acquired by eating Ring of Brodgar, Honey bun, Cooked Rabbit Meat, Delicious Deer Dogs.
Con: Affects Max HP and the stamina drain caused by swimming. 2 Max HP per Con.
Acquired by eating most Cow related meat products and Pirohskis.
Per: In conjunction with Exploration, determines the visibility of certain objects in the wild (Inkweed, Rustroot, Chantrelles)
Acquired by eating Cooked Deer Meat, Lamb Sausage, and small amounts in various other foods.
Cha: I believe the only use for Charisma right now is that 25 is required to become Chieftain of a village.
Acquired by eating Grapes, Bear Salami, Cooked Lamb Meat, Raisin Muffins, and small amounts can be found in other foods.
Dex: Affects Sewing and Leatherworking.
Acquired by eating Pirohski's, and chantrelles.
Psy: Affects high-end crafting. Currently only affects Jewelery making in conjunction with smithing I believe.
Acquired exclusively by eating Rings of Brodgar.
Skills are all increased through LP. Skills can never raise the quality of crafted items. Instead the formula is something like this: If the weighted average of the materials involved in the crafting process is greater than your skill, your skill is averaged into it to lower the outcome. If the weighted average is lower than your skill, then no change is made and you will output the maximum quality of object using those materials. In addition, some skills are used in conjunction with a stat in the formula. when this is the case (as it is with sewing/dex and smithing/str and smithing/psy) the formula checks the square root of the product of the skill and stat against the weighted average of the materials. i.e. (stat * skill)^(0.5) So if you plan to specialize in smithing, you may want to keep your str and psy up. and if you want to specialize in sewing, you will need to keep your dex up as well.
Combat Skills: Unarmed, Melee, MarksmanshipThese skills affect your chance to hit and chance to dodge while using each of the 3 combat styles, with the exception of Marksmanship which only affects chance to hit and relies on your unarmed skill to determine dodge rate. Marksmanship also affects the quality of bows.
Exploration: In conjunction with Perception affects your ability to see various objects in the wild (inkweed, rustroot, chantrelles)
Stealth: Affects the chance for your crimes to be detected by other players (I believe that perception may be involved here, and it is checked against the other player's agi and exploration in order for them to see your scents)
Survival: Affects most objects crafted with the basic renewable resources in the game (Stone axes, Bone Saws, Arrows, Etc...) Also plays a role in the planting of trees at the actual planting stage (after they have been on the table) Also affects the quality of materials you get from harvesting an animal (skin, meat, bones, special items such as antlers, tusks, and teeth)
I believe I basically covered the other skills in that they simply affect the obvious. Farming throttles your seed quality, Sewing/dex throttles your leather/cloth product's quality, smithing/str throttles your metal product's quality, smithing/psy throttles your jewelery product's quality, and carpentry throttles wooden product's quality (most importantly, the quality of boards you get from sawing logs.)
Note: I do not mean to imply that the skill/stat combos above represent the division of the stat from the skill, rather just to indicate that the two are used in the formula as previously mentioned.
It is important to note that
skills do not affect the quality of buildable objects (any objects that remain on the world screen and cannot be placed into your inventory, such as meat grinders, tanning tubs, herbalist tables, etc...) These objects' qualities are based solely on the weighted average of the materials used in their creation.
Hope this helps. If anyone can think of anything I missed I'll be happy to update this post with the added information.
You may also want to read up about the colors of the stats in the FEP bar as well as various other aspects in this thread:
http://www.havenandhearth.com/forum/viewtopic.php?f=2&t=84