Well, if your character's skills are too low, and you are finding the game too hard, you could start with a more-skilled character, or a starting scenario that begins with items.
Barring that option, the best thing to trade for upgraded items in the early game is animal pelts. Even with crappy tools, you can make traps. If your trapping skill is too poor, you can make javelins, and approach prey with stealth. If you have neither spear skill nor stealth skill nor trap skill, your character will have a hard time finding pelts. If your character's skills are decent but you are having trouble encountering animals, you are probably in a low-game area. Relocate to a different area. If you travel enough, you will surely encounter squirrels, which even a low-skill naked character can easily kill with rocks. If you obtain enough squirrel skins, you can trade for a decent-quality knife or handaxe and begin making finer tools.
If your fish are spoiling before you can reach town, you need to find a fishing source closer to town. Some towns are located right near lakes or rivers. Salmon and trout (found in rapids) are worth a decent price, and if you have decent cooking skill you can increase the price even more. Cooking also makes them last longer. If need be, you can trade for non-spoilable cheap items like arrows and then stockpile those, trading them back for a knife or handaxe once you've obtained enough.
Good luck! Think laterally and don't give up, sooner or later you will surely succeed.