Early in the game I boosted strength a bit (in part for the regeneration bonus), and mostly relied on food after fights in order to speed up healing. After you go up a few levels you should start coming across jewellery with regeneration bonuses and later healing aura enchantments.
I think potions are pretty much required for tougher fights, though you should find plenty of potions, as well as the ingredients to make your own (after you have the battle tower you effectively have access to unlimited potions, with a little bit of time sending your runners out for ingredients). There were large sections of the game where I didn't need potions, though.
For skills I put 1 point in Healing and Regenerate (after level 15). Additional levels of either skill don't give as much of a benefit per skill point, but I may eventually boost them more when I have a bunch of skill points I don't know what to do with (my ranger is currently level 37, at the start of FoV). One level of the Evade skill is also quite handy, to give a chance of avoiding melee attacks (higher levels giving a lower return on investment).
If you are going to fall back on melee combat (ie duel wield magical one handed weapons, with Increased Magical Damage enchantment bonuses, when available), a level of Life Leech would also help.
With enchantments I eventually put Life Line on all my armour as a first choice, followed by Increased Mana (or in one case Magic Protection). Before you get the battle tower you will not have the ingredients to upgrade all your armour each time you find a higher level enchantment formula, but most of the time you should be able to put the highest level you have on each new piece of equipment you upgrade to (at least if you switch equipment about the same amount I did). The first enchanter is available about level 12, or so, depending on how you explore Broken Valley.
I tried dodging a bit early in the game, but found jumping or running past or away from an opponents was much easier. Once I got to a high enough level to put a few points into Splitting Arrows, I didn't need to avoid as many opponents, as it could take out most generic enemy at close range in one hit; Stun Arrows also came in very handy at the start of the game. Firewall should help with opponents that get too close to a mage character, and Confusion should help keep a few of them from getting close.
I am playing on nightmare difficulty. You should have an easier time in terms of combat and healing if you play on a lower difficulty level.
