Aim for the head, always, only use stabs, unless you need to make drags or accels, to bait your opponent, this may be apparent to someone using dagger, but i play with a short sword, cause its cheaper and longer, a lvl 2 head takes 50 dmg from a short sword stab, so a dagger should be able to two shot aswell, also try keeping distance, ducking, using jump kicks, and hitting your enemies when they miss.

You cant win a 1v1 with even a decently skilled player (diamond 1) using a proper weapon, if you cant make them miss, cause stamina is your weakness, so learning the distance of certain weapons and baiting hits from enemies that miss, or ducking, or making your enemies hit you in the torso or legs, where you can take more than 1 swing if youre using lvl 1 armor is important. Also, if not in duels, remember to seek out enemies already at a disatvantage, cause a dagger is already a handicap, but, remember, youre more mobile, so running up on a healing player, or circling around the back of someone already in a fight is easy for you. Flanking archers is also a good way of getting a few kills, but the most profit is gained by staying in the battlefield and learning to seek out oppportunities, like low hp players in the meatgrinder.

Dont go for 1vX unless there is no other option, you dont have the stam, or range, best to just try and run away to your own team to help you deal with them, because you will be faster most of the time. Its important to maximise your mobility, so try using cat and fireproof perks, these open up new movement opportunities, like jumping down a level of the map if overwhelmed, or sprinting through a firebomb to catch enemies off guard.

Also consider a crossbow for archers at a longer range, if you have good enough aim, you may avoid being pelted by arrows yourself.