When playing with my friends I found interesting to give consequences to the actions of their characters that go beyond hacking off their HP, but that still have some “mechanical” effect on their characters.
In the context of OSR/NSR there are games that do this, as Mausritter and Cairn. Even DnD 5e has conditions + fatigue in their system, although they are cumbersome for my taste, and remembering the different steps and effects of fatigue is always a challenge.
Inspired by these OSR/NSR games (and some PbtA games) I use the same umbrella-term conditions to treat things that affect character that go beyond “common” damage.
This is how I define/use conditions:
Conditions are adverse states of mind or spirit, or physical injuries or weaknesses.
They are defined with a word that self explains what it is.
Their name also makes evident when and how they will be affecting the players.
A complication has a negative number associated to it.
If you get the same condition more than once, you add their numbers.
The number modifies your roll when your action is affected by the condition.
If you declare that you are working towards overcoming the condition, every day doing so decrease the magnitude of the number associated with the complication until it reaches 0. Then the condition is overcome.
Simple, no?
Examples: So if you have a player that eats something bad, give them food poison -1.
If someone is lure by a supernatural seductive creature, give them charmed -1.
If they just got out of a dangerous situation, then they will be shaken -1, and if that same day they got again into another dangerous situation, then they will be shaken -2.
Any of these conditions will affect them when it makes sense: Food poison -1 affects anything that requires fast, powerful movements or the toughness of their body. Charmed -1 will affect them when interacting with the being that charmed the character. Shaken -2 will affect anything that requires bravery or clarity of mind.
To overcome conditions the players can declare something that makes sense: Food poison -1 could be overcome by one day of a bland diet or by using some herbal remedy. Charmed -1 could be overcome by maintaining distance by one day from its source. Shocked -2 could be overcome by staying away from danger for two days or doing something that restore the confidence and calms the character.
But you could ask: Where in my character sheet I write these conditions down?, well, anywhere you want.
But if you are playing a game that uses slots for items, then use these, in the same way that Mausritter and Cairn have done it before:
Conditions are written in the same space reserved for items.
If you don't have space for them, you have to drop an item.
And this is all, easy, no particular rules for each condition, they only affect your character when it makes sense, modifying your role, and they can be overcome in a number of days equal to this modifier.