STAY IN CHARACTER. Remember you aren’t trying to win you are trying to stay in character. Don’t ask how can I win a fight? Instead, ask yourself how would my character react to this, would they fight, run, stay at a distance. You cant win a game of d and d so don’t waste your time trying.
DONT OVERTHINK IT. when you overthink a character you ruin it. If your character has 80 pages of backstory you have no room to grow and develop. Your character should have personality points they always follow, especially in decision making, and the back story should give a reason for this personality. Don’t spend weeks on a backstory for a character who may die in one hour.
KEEP IT REALISTIC. You should know the lore of the world you are playing to successfully role play in said world, if your character breaks the lore you better be able to back up your choice. I.e if your character is from an Asian based continent and is now in somewhere based on Britain, why did they come here? Did something drive them out of Asia? Explain these, maybe work them into your characters demeanour and actions.
DONT BE OP. having an overpowered character can ruin a campaign for everyone. If your character is too powerful in their stats it can make the rest of the party feel almost useless, and it is not realistic for a character to be that overpowered. Other than stats having an overpowered personality can also suck, not only for the other party members but, for you as well. If your character is overpowered they come off as a mary sue. if they don’t have enough flaws it will be hard to play. Generally, in story writing, your character must be balanced. If you start with a character who is everything they have no room to grow or develop. Your party members characters will grow and flourish over time if yours is too overpowered, to begin with, you may get left in the dust.
YOU CONTROL YOUR CHARACTER NOT YOUR WORLD. With your character, you have complete control when it comes to the wold, not so much. In this world your dm is god, if they don’t say something is true, it isn’t. You cant control the world around you or any other characters. Your dm didn’t create the world, they ARE the world. Your dm controls how every character interacts with you and you cannot force a relationship with, or control, anything outside of your character. NPCs are reactionary characters, if you are rude to them they will react as such. Although your dm is giving you the messages they are not out to get you, only staying in character.
DONT BE ANNOYING!. Let’s just say that annoyed party members may “accidentally” kill you in your sleep. Always remember “Wheaton’s Law”