No matter what you do you will get your ass kicked in the beginning. It is part of the design. Here's some tips.
There is a limited amount of xp in the game so grind as much xp as you can. This means doing as many quests and killing as many monsters as you can. Before you choose which camp to join, you can complete many sidequests at each camp. After each chapter some monsters will respawn so keep an eye out for them as you walk around the map. At first you will be very weak and unable to kill more than scavengers but soon you will be able to kill tougher and tougher monsters, so return to the tough monsters you found after you feel strong enough to take them on. They are usually guarding something nice.
Just leveling up doesn't do much, you need to spend your LP. I would highly recommend leveling up your weapon skill as soon as you can. All characters, even mages, archers, and 2hand swordsmen, would do well to at least pick up the first level of One Handed skill. This will make combat much less difficult as your hero will have more effective combat animations and will be more responsive when fighting. From there you can pick how you want to develop your character (melee needs str, mages need mana, etc) but first level of One Handed is the minimum for everyone. Personally I like going full strength with a 2 hander.
You might be hard for money/ore at first but you eventually get tons. Your armor, not your level, is the most important thing for survivability, and while you get a few free sets of armor, don't hesitate to splurge when new armor becomes available from the vendors. New armor will unlock throughout the game as you progress through the plot.
Pay attention to the enemy AI. Learning how to deal with each type of enemy is key for survivability. Also you can pull one monster away from a pack by shooting it then running away. The pack will chase you, but if you periodically shoot the same monster while running away, the rest of the pack will give up and you can fight him alone. As well you may notice the pathing AI is not very smart and you can trick enemies into taking circuitous paths pretty easily.