1. Better food. Get a piggy farm set up, run screaming through swamp to find the swamp veggie (onion or turnip i think..). Others have mentioned this
2. Use a bronze round shield so you can parry. Bone looks cool but is no good here. The knockback shields have their uses, some quite funny, but its ultimately not worth most of the time. Im sure someone can debate that but i find it to be true.
3. Consider going out on the sea to get an Abyssal Razor dagger
4. Poison mead
5. With usage of fire arrows, or with some parrying (bronze shield or better only), or both, you can kill an abomination or two and craft the root chest piece. It gives resistance to piercing, which will help with draugr archers. This may not be worth the time because they have a habit of booking it when they get low health.
6. Running away is perfectly fine. Not every fight is worth winning.
7. Consider terraforming paths, and scout things out and drop pins on locations for later.
8. Until you are an age ahead of iron its really bad to go in the swamp unrested. Your stamina will be nonexistent
9. Shoot corpse piles from a distance or avoid them. They have nothing interesting anyway.
10. So if you find a flame geyser in the swamp, kill the fire elementals. Don't be afraid. The swamp makes you wet forever and unless you are insanely unlucky or fantastically careless they cant kill you. They drop surtling cores. This flame geyser is also the most amazing way to kill an abomination, taking a few seconds. The elementals also respawn seemingly infinitely after a delay.