Compromise- Your idea might be great but in the end there's a few things that might bug your partner the wrong way. Coming up with solutions for these things and creating new twists and turns for your idea can be a handy skill as it can lead to more involvement from your partner. Collaboration on ideas is a key thing when creating a long lasting plot. For example, your potential partner lives the idea about a werewolf and a vampire but doesn't like the idea of blood and gore. You can come up with a neat idea like the vampires don't feed on blood but instead on life force or energy. Improve courses can help with this actually as it can help you think on your feet while planning the RP or actually RPing.

Don't over plan- Over planning a plot can be a big turn off when people are looking for an RP. Now if you wish to attract others who over plot obviously over plot in your interest check and go into create detail. But if you want to seek a broader audience be vague in your idea and then plot with your partner about the nitty gritty details. Now there is also just jumping into a very under planned RP as well which is also what some people like. What you express in your interest check plots will determine the kind of people you RP with.