Ok grumpypants OP
Here are my tips.
Get followers if you're going to be fighting other sentient beings. Fortresses generallly have lots of soldiers. Even most hamlets have 1 or 2 if you look hard enough.
Training:Lots of companions can make it hard to get exp though. So to train i suggest hunting animals while alone. If it's a non-aggressive animal and you sneak up on it you can grapple it so it won't get away, then watch the exp roll in as it struggles and kicks you. Or if you can get a sentient enemy alone disarm him and make the fight last a while so your guy can practice dodging and such.
Sneak EVERYWHERE. You will quickly get very good at it. (Legendary Sneak basically breaks the game)
Swim. Drowning sucks, and swimming builds useful stats. If you want to powerlevel a bit, find a pool, and sneak while swimming laps.
Finding/Picking Equipment:If looting one of your former fortresses for steel or adamantine gear is not an option...
Steal from a Human fortress or keep. This is a minor exploit. the items are not considered owned and are free for the taking.
If there is no good stuff in the tower you can go into the dungeon. often scattered items there but also enemies. So risky.
Best armor items to get are probably an iron mail shirt, breastplate and helm, and any cloaks you can find.
Metal gauntlets, boots and greaves pick up later when your character has the armor skill to move fast in that much weight.
Buy or loot leather boots and gauntlets if you can find them to wear until then. (Unless you get lucky and find an unusually light weight piece of armor, which happens sometimes. 1 kg iron boots/gauntlets are a real treasure in adventure mode. Most weigh 15)
Extra clothing layers increase survivability a little and don't weigh much.
Silver is best for blunt weapons. Iron/Bronze for sharp ones.
Loadout:My standard combat load is Primary Weapon in one hand, Shield and knife/dagger in the other.
quiver of arrows/bolts for throwing. This gives a lot of flexiblity and reduncancy.
I favor swords as my primary, but YMMV. Most weapons have an application in which they shine.
(My preferance runs roughly: sword, hammer, spear, morningstar, all-others)
Combat:Get stealth kills if you can.
(sneak, strangle, throat slit works well. So do arrows hurled from the shadows, then ganking the people who faint from chipped bones)
When spotted, let enemies come to you, throw bolts as they close.
In melee, systematically disable the easiest to hit body parts one after the other. While waiting for a chance to strike the weapon hand and head.
If the odds become more than 2-1 in melee range early on RUN. Get behind something solid, sneak. Go back to start of this section.
Take every combat seriously, always assume the enemy is stronger than you and fight accordingly.