Use a club (or a torch) against the skeletons. That spear is going in between those brittle old bones and doing little damage. A nice solid whack with a club will break those bones. A torch will break those bones and set them on fire. (When your skill is in the single digits the torch will do slightly more damage than the club to skeletons)

Move slowly. If you see it before it sees you, you can get a shot in with your bow. If you hit the skeleton before it has an exclamation point over its head that shot will do double damage. You can then activate your wooden shield and your club quickly if you put them in the numbered hot key slots in your inventory.

The shield is important throughout the entire game. Make sure you have one and learn how to time your block. A parry block is trickier to learn how to use but more effective. Time your defensive moves. Right click to block. If you right click just as it starts to swing (or shoot an arrow) you parry block (if the shield is a buckler style shield) and stop more damage from hitting you. This can also stagger the opponent if its not too much more powerful than you are. A staggered opponent will stand there with arms windmilling for a couple seconds. If you hit them when they are staggered you do double damage.

You can also do the roll dodge. While in motion press and hold the right mouse button and then press the space bar. If you use the same timing as the parry block you will roll out of the way and take no damage from the attack. You have to get the timing right though, if you hit the mouse and the space bar at the same time you will jump and the enemy will hit you and the more powerful ones will send you flying (literally) this can be bad if you are fighting on a slope as falling damage can also kill you especially with early game gear and bad/no food.