Rping is fun, you are getting into a good hobby that can improve your writing skill, but still, there is no need to get worried about it. A few things I always keep in mind is that you have no control over others... Even if that just means making contact with them, you always have to give him the moment to move out of the way if that is what they want to do... This is especially important in fighting, provided that the opposite person isn't giving his character too much power, you should be able to get a hit in.

Also, detail is your friend. When you are writing, the picture that you can create for your rping partner can be as vivid as you want it to be, so make it as vivid as possible :D. A detailed rper causes less confusion and is well liked by his fellow players.

If there is anything specific you want to ask about, go ahead and hit me up, I've been doing this for years now, so I've been around the block. Good luck and happy rping.