In regard to question #1, try increasing your level before taking on more challenging opponents (the poachers).
In regard to question #3, using your best attack is probably best for you now. That way you'll do the most damage.
If you scroll over your current weapon, you'll notice that there are three types of attack:
- Chop, accomplished by standing still or moving diagonally
- Slash, accomplished by moving side to side
- Thrust, done by moving forward or back
Whichever does the most damage is referred to as your best attack.
In regard to question #4, your armor rating is totally dependent to your skill for that particular piece. So, if your light armor skill is high, you'll receive more protection than if it were low. Same goes for unarmored, medium, and heavy.
And, as Mel has pointed out, your armor will give you less protection as it deteriorates. So make sure to keep in top condition, especially your chest piece (which provides 40% of your total armor rating).
If you're going to be doing guild quests, I can almost guarantee you you'll be training your skills.
Also, if I were you, I'd try to raise my sneak and marksmanship first. That way, you can avoid any unnecessary risks; and those that you do have to face, you'll be able to face from
far away.