HunterZ: the lack of ability to land blows
Are your hits failing, or being blocked (colour indicator)?
If they are blocked, keep in mind that both you and your enemies can only parry once each turn, meaning that you should always try to hit one enemy with at least two of your own characters (and wherever you can, let the weaker one hit first).
Are you attacking aggressive, careful, or neutral?
If you can afford it, aggressive attacks are the way to go.
HunterZ: saps my patience such that I usually just switch to computer fighting mode at some point
I won't lie to you, fighting in RoA is going to be tedious and will inevitably take some time, even if your group is the far superior, but there are some 'short cuts'. First of all, use your missile weapons whenever and wherever you can. And when you're facing real trouble (or are in a real hurry), magic can often be the perfect choice. Talimee can render an opponent unable to attack or parry for three turns with her lightning spell and her fulminictus sure leaves a dent. Whenever you're too slow, her acceleratus can help as well.
Tamion's evil eye is a scary vision for your enemies, as they are forced into fighting their former friends and thus can speed up your success quite a bit.
Yarano can try all, lightning, fulminictus, ignifaxus, paralyze, magic armour, ...
But one thing you're going to find out sooner than later, computer assisted combat is... rather worthless. The AI isn't very intelligent and is bound to take some very suboptimal strategies.
HunterZ: run away when low on hit points
That actually still grants you experience, you simply lack a bit of loot. There are even whole spells focused solely on getting your opponent to flee from the battle (RoA is a lot less bloodthirsty there than the average game, even your own characters can go unconscious instead of plain out death ;)). I just mention that this is a viable alternative, but I often tend to hunt down my prey as well *grins evil*
Edit:
Since I got a bit curious, I started to look around and would like to add a few points to what I said previously.
First of all, in a different thread you wrote, 'I feel that I'm not likely to fare better than the computer at building and growing my party (...) in novice mode'.
Now I do not claim to have any insight on the source code, but there are claims that fights are 'easier' in novice mode. Despite this little bonus, I have a feeling that (most unfortunately) the novice mode is more tricky to play, since according to some reports, the computer doesn't specialise, which would be somewhat important (even more so in combat!).
If the algorithm follows the same pattern as it does in the original pen and paper DSA (3) rule-set, you're simply throwing a 20 sided dice, where 20 is automatic [critical] failure (seems to be implemented as there's a blue colour on attacks) and any number below your AT value indicates success. This would mean a maximum chance of 95% and this value is definitely reachable near the end of the game.
A fighter with 13 IN/AG/ST advancing five levels without failure and wearing a magical item with ST+5 would end up with a base AT value of 10. If the fighter has the correct entity, the sword value (again without failure) would be at 12, which means you could distribute 9 points on AT and 3 on PA and have a total of 19 AT/ 13 PA (actually you can even get magically enhanced swords giving you another bonus, so you'd end up with 19/17 as maximum values), which should equal 95% chance of success (on the test, not talking about your opponents parry).
You won't reach these values with the predefined party on novice mode though (and I don't know the consequences of a value of 20, or actually of 19 in aggressive attack mode).
Since you wondered about your pre-made characters' skill profiencies and I've got the game open anyway, I'm going to include a brief overview here ;)
Arbosh: Axes and Cutting Weapons, Danger Sense and Perception, Locks, Self Control, Evaluate. This makes him a good leader in dungeons and a decent fighter.
Rhenaya: Swords (and two handed, though these are going to have a lesser chance to hit, so if you've already got trouble there...), Self Control. Basically, she's your main fighter.
Hjaldis: Axes and Cutting weapons, Self control. A decent fighter.
Talimee: Pointed Weapons, Swords and especially Missile Weapons, everything nature related, Danger Sense and Perception. She should lead your party in the wilderness and use her bow together with magic (important combat spells described earlier).
Tamion: Pole Arms, might use throwing weapons as well, everything nature related, Danger Sense and Perception. A viable alternative to Talimee for leading the party in the wilderness. Either of the two should collect herbs and the other food while camping. Both can take decent care of wounds either through magic or talents.
Yarano: Pole Arms and maybe a possibility to throw something here as well, Alchemy. When there's a poison to be mixed, he's your man, not to mention the enormous potential when it comes to combat related magic.
I'd use either Yarano or Hjaldis as leader inside cities. Neither is really well suited for the task, but they are the best you can muster. Hjaldis might score well with men due to her charm and her talent to seduce, but Yarano knows his way around the city a bit better.
I hope that might have been of help.