OK I'm going to just vomit out some basic notes for possible uses for personal magic in combat. We are going to go by discipline and some of these might be wrong or right, so I welcome anyone more knowledgeable in magic to contribute.
Reimancy
Alright so this is the easiest one as reimancy is very much a combat discipline of magic. When it comes to using reimancy in battle there are a number of factors that should be taken into account that determine effectiveness. Skill level, experience in combat and stressful casting, range, elements used, and availability of the elements nearby are the big ones I can think of right off the top of my head.
The level where reimancy in combat really becomes feasible is about in the 15 XP- 20 XP range if we are going by pure stats here. Anyone before that is going to have trouble just casting a firebolt. The ideal stage would be competent at the very least. Firebolts are simply balls of flame that vary slightly in size and are a quick cast. However even with just this one spell one can likely stun an a opponent at the very least if they are not another reimancer.
One should take into account that res is a very flexible substance and can phase change to suit the wizards needs. It is said that breathing in foreign res is like breathing in fire, it burns badly and is quite painful. At the least it could incapacitate an opponent on its own most likely. It could then be transmuted at fill from inside the opponents body, killing them.
Casting, however takes quite a bit of time for anything say below expert for spells useable in combat. Trying for speedy casting can easily trap a reimancer into possibly overgiving and will definitely effect their ability to function in combat.
Elements that are used are also an important factor, obviously is most combat situations the elements most often used are fire, earth, and lighting so I will cover them at the moment. Fire is devastating when used correctly, however the ideal use for fire would not be a massive fire storm but an attack from within. Carpet the field with gaseous res and let your opponents take it in, then simply transmute it to fire on the inside and cook them from the inside. A competent reimancer or higher would be best for this method as the longer the range you can have a wider and safer area of affect. Even armor wouldn't be able to save you from this.
Earth can create constructs to crush an opponent, its very potent because there are quite a few materials always on hand for its use meaning chances for bigger casting. There are numerous methods to kill an opponent this way but the simplest and most crude would be literally to lob a big rock at them. Or stone them to death with a bunch of smaller rocks. The downside to this would be that some armor can deal with some of these effects. An earth spike might do the trick in that regard as it gives you the piercing force you need.
Lightning is possibly the most devastating and dangerous force in reimancy. There are three factors to consider with lightning, explosive force, heat, and sound. You all know what thunder sounds like right? Well, imagine being right next to the source of that sound. Yeah, it would suck pretty hard an could even deafen you. Heat and explosive force are the things that leave nice little holes in your chest cavity. A lightning bolt could easily kill even an armored opponent an unless they have flux or something to alter their speed they won't be able to dodge it. However, it is best to ensure the lightning is cast well away from the wizard's body, otherwise it could kill him.
Reimancy against non wizard: If a reimancer is smart then even a competent reimancers should be able to kill most anyone who excels in melee combat. Those with bows might find it much more easy to kill a reimancer and getting in close to them will typically be bad as the majority of reimancers are not the best in physical battles. The ideal situation would be for a reimancer to attack from range at all times, keeping the opponent far from them.
Reimancy against reimancy: This can get really nasty really fast depending on the skill of both reimancers. Res can effectively act as a shield against other elemental attacks, the recommended course of action her is to be smart about res usage and to wear the opponent out first. Strike first if you can but have a defense ready. In the case with fighting another reimancer, always be ready to fight as dirty as possible and as brutally as necessary.
This is really, really rough as it is late and I'm tired but I figured I should get something up here at least. I'll edit in more and add other disciplines later.