Folk: Ulvar
Class: (OPTIONAL) Hammer or Great Axe. Whatever your play style
Trait: Berserker
Equipment: Ideally, try to get Sveid's Endless Pockets (fire element) as early as possible

Strategy
Some kiting, 1 hit at a time, be patient, gather coin. Basically, the Sveid armor will grant you 1% damage every 5 coins. As a Beresrker, you cannot improve armor, so this is really the only item that is worth it. Coin increases DPS. As a Berserker, every damage % grants you more HP. The more damage, the more health. You will not need that much mana, so destroy EVERY useless card for more dmg%, therefore more HP. If you get far enough, you will have a huge HP pool.

Combat
Elites and minions
With this build, you will be somewhat squishy, so avoid being hit. BE PATIENT. You should always try to line up the enemies so that you do not need to defend against 2-5 strikes at once. Especially when fighting trolls. Focus on 1 individual, hold and charge your main attack, wait a few moments for enemy to approach and release. Most hits will stun the lower level enemies since you have a heavy weapon. Breaking their posture will be easy.

Bosses
Strat 1: RUN and sprint around them, then hit them when they have performed their flurry of attacks.
Start 2: Stay close, pay attention and dodge to become frenzied, then perfect guard before attacking. The few moments of invulnerability is great to soak 1-2 hits. Do not perfect guard on the Boss' first strike. It's wasted.

Folk: Ulvar or Human
Class: (OPTIONAL) Greatsword
Trait: Parrier
Equipment: Get Sveid's Endless Pockets (fire element) as early as possible and (OPTIONAL) or any armor that grants something upon perfect guard (see picture), Greatsword of the Mountain Guard, which grants frost damage on Perfect Guard

Strategy
Guard every hit, as it will never decrease your posture. With some practice, contrary to Dark Souls, you will easily be able to guard most hits and gain incredible amounts of focus. Since you chose the greatsword class, you dmg will be 80% higher after Perfect Guard.

Bosses
Stay close, pay attention and Guard every hit. As an added bonus, you can dodge, then guard, then hit, then guard again, etc.

Here is a great synergy I have built on my last run. Screenshot after defeating the 2nd boss.