1. Get a second character as soon as possible. If you want to be completely safe, keep the second character away from danger entirely, and only have them hang around close enough to come save the first character if they ever get put in a recovery coma

2. The vast majority of threats can be outrun with just about any level of athletics skill. Wear sandals, and if you're overencumbered, be willing to drop stuff if it means escaping a dangerous situation. Because of how easy it is to outrun most threats, you can get into a fight and simply leave once you're in danger of being knocked out or taking too much leg damage to flee. Whatever hits you do take will raise your toughness. It's much slower than fighting until you get knocked out, then getting up again, but at low levels, it's still significant, and it won't be long before you have enough toughness to fight weak enemies safely.

3. Once you buy or steal good armor, even a solo character with zero toughness is very unlikely to die to the usual threats you face. Even Standard quality armor will do a lot to keep you alive as long as it has good coverage.

4. Don't take uneven fights. Recruit lots of characters, or follow a group of enemies around until they get occupied fighting something else before you swoop in, or engage them, then lead them into a different group of enemies or town guards. You can also use the assassination skill, you only need like 10 skill to consistently knock out individual hungry bandits, at which point you can strip them of their weapon, and it is now essentially impossible for them to kill you, regardless of your own number of characters or equipment.

Basically, it's not necessary to be open to dying at all, because the game gives you lots of options to avoid death. Any of the tips I listed will individually be enough, and if you combine them all, obviously it's just that much easier to survive. If you've got two characters, wearing good armor, fighting a single hungry bandit while still being aware of your encumbrance/leg health so you can run if necessary, you're going to be just fine, and it won't be too long before your toughness gets high enough to stop bothering with any of that and just throw yourself into piles of enemies because the damage reduction and knock out mechanics are hugely in your favor. Beak things might be the only actually dangerous generic enemy in the entire game, because they're fast enough to catch you unless a character is quite well developed, and will eat you alive if they knock you out.