I think a genuine desire to make RP interesting for the other party goes a long way, and I’d argue that it’s more important than excellent writing. Obviously this is a writing hobby, but I’ve seen decent writing be elevated significantly by a person who’s very skilled at RPing, and conversely seen amazing writers who I absolutely hate to play with because they just don’t think about anyone but themselves.
For me to personally be interesting to others (and I’m sure all of this is going to be really obvious but YOU ASKED THE QUESTION OK), I try to:
- Look up the person I’m RPing with’s sheet/hooks/background before we play for the first time so I can try to see their characterization (I don’t read every single background in detail but I do try to have an idea of who this character is, and then think not just about how my guy would react to what they do, but how their guy might react to what I do)
- Think about the ways where my character can be silly/dumb/wrong, then BE WILLING to look silly/dumb/wrong, often purposefully being silly/dumb/wrong bc humor like @sao said
- Use props (I especially like to use kids but also animals are fun, or random NPCs who are there for a purpose that others can react to)
- Think about when to press myself forward and when to pull back to allow someone else’s character to shine, especially if it’s a scene where their character is more suited to whatever’s happening
ANYWAY those are my immediate thoughts!

You are also A+ excellent. Also 
