Do Some Background Investigation
If you have a bit of extra time, try to do a bit of background investigation. Depending on what role you're playing, it may require a bit more time to learn. If you're playing an escort, you may want to look at online communities to find out about proper procedures and safety information that career escorts use. If you're going to be a police officer, do research into the exact procedures that an officer would use when making an arrest or taking someone into custody. Not only will this little bit of extra knowledge make your role play more realistic, but you'll also be learning something new!
Set Up a Safeword
While role playing isn't exactly BDSM, you may find it helpful to set up a safeword before you delve into your characters. Depending on what characters you choose and how the power is balanced between those two characters, you don't want to confuse a playful, "No, please, don't!" with a serious, "Please stop that now." Discussing a safeword in advance lets you both relax and get deeper into your roles. You both know that you'll use an unrelated word if anything is serious. You can feel safe knowing that your captive saying "Oh, please, no!" is entirely playful.
Bring Up Any Requests Beforehand
Your partner can't read your mind, and you can't read your partner's mind. If you want your role play to go as smoothly as possible, you should both discuss any preferences beforehand. You may not know that your partner fantasizes about the police officer having anal sex with his captive. Your partner may not know that your ideal babysitter scenario uses handcuffs. To get your realistic role play as close to your fantasies as possible, take some time beforehand to discuss what you'd really like to see happen.
Now that you have a good idea of how to best pull off your favorite role play fantasies, you and your partner are equipped with all of the knowledge you need for a more satisfying playtime. Get your roles in mind and jump straight into the sex you've always dreamed of.