There are tons of statistics that apply to a character only, and these are just a few tips and methods to boosting them an exponential amount in the beginning of the game.
The "Hostage" MethodEdit
This tactic will raise both the Field Medic and other fighting stats, dependent on what weapon(s) you are using. Find any bandit who is knocked unconscious, but still alive. As of the current game version, you can use First Aid on them, so go ahead and do that. Once the bandit is all patched up, have one of your companions pick him up. Save the game. Wait until he's all healed up, then save again. Put down the bandit, and if he doesn't get up and attack you, save and then load back. He will get up and try to fight you, have all of your companions gang up and beat him down. Both your companions and the bandit improve from the fight, so the bandit won't be too weak to train on after a while, since he starts scaling with you as you fight him. Keep repeating this if you're having trouble with the 'Safety in numbers' method. (This method is also good for improving individual companions, for example, their defensive ability against a bandit with a high attack chance. It also improves the Field Medic skill.)
The "Body Snatcher" MethodEdit
This tactic will raise a character's strength. If you wish to build your strength up early in the game go to the bar and hire someone for 700 Cats. Then simply carry him around and watch your strength grow.
High Risk High Reward, quick melee skill gainEdit
An effective yet high risk method of raising melee attack and defence quickly is by lowering your combat skills. This happens when you equip a backpack, chainmail, various helms or some armours such as the Holy Chest Plate. In combat, when your stats show a negative in brackets (e.g -10 from a traders large backpack) this is the base used to calculate your experience gain. Meaning, if you have 20 melee attack normally and find it is levelling slowly, if you equip a traders large backpack it will be counted as 10. You will then gain the amount of exp that someone with 10 melee attack would. This is also true of Melee Defence.
Pieces of equipment that lower your combat abilities are cumulative, for example a large traders backpack in addition to chainmail, the holy chest plate and a tin can helmet would lower your skills by (-18). Thus allowing for quicker exp gain.