I found these things a little while back and thought it a good exercise for not only learning about other people's train of thought, but also expanding on your own.
I started RPing when I was very young, barely a teenager for the most part and I've been doing it ever since through thick and thin. I stumbled upon GaiaOnline and the idea of making characters and telling stories was what pulled me into all of it. Seeing people around that place showcase their artwork and use it as their characters and the like was what got me in to drawing my own. When I saw how the artists received so much respect and attention, I kind of wanted some of that for myself since I had had a pretty miserable life thus far. I wasn't very good back then, I'll openly admit that. I suppose it was the environment that paid into it since everyone there just wanted to try and "out badass" each other and RPs often lasted for only a day.
Eventually I found that there were actually whole sites dedicated to RPing, like this one. I've only been to a few and become engrained in the communities of even less since I tend to gravitate toward smaller groups of friendlier people as opposed to large collections who barely know each other.
Concerning the types of RPs I join, there's not much to say really. For the most part I'll join anything that has the promise of character development beyond fight-fight-fight-fight or the polar opposite. I'm usually much more content joining something else as opposed to making my own since when I do make something, it tends to take it's toll on me.
I've made very few RPs during my time within this circle but when I do, there's some common elements I tend to carry over from story to story. I feel that giving players a goal in terms of developing their characters is always something that helps to keep them hooked. Providing players with statistics to develop as well as equipment to find is something I enjoy doing as most of you have experienced with "Veil of the Malfested". I made a list of equipment for people to use in order to plot out what they wanted to do and a statistics system that lacked complication as an easy means of increasing their character's strength. Within my own stories, I often make characters of imposing presence to persuasion in order to drive the story forward. Allowing the players to guide themselves is all well and good but it can often lead to derailment or loss of direction before inevitably coming to an early conclusion. As such, characters along the lines of Velka, Elise and Freya are often present to help keep things moving forward.
As for my own characters, I consider my wide comfort zone a strength; there's not a lot of archetypes I can't fill although I, like everyone else, have a niche. I'm not a fan of having a "tag along" kind of character, that being someone's who's just kind of... there without ever really leaving a footprint. I always try to create balance with my characters, that being giving them strengths as well as weaknesses. I have characters along the lines of Noel who wield massive amounts of power, but have a crippling cowardice to hold them back.
My strongest points would probably be my ability to create strong, charismatic protagonists and incredibly imposing antagonists with antagonists being my stronger suit. My weakest point is most certainly my inability to plan ahead and for the most part, I don't think I can come up with a way to improve it organically.
Finally, music and visual aid are BIG parts of my RPing world. Whether I'm making my own roleplay or participating in someone elses, those two things are very important to me. Music in particular I feel drives everything. Giving characters a theme song or two as well as providing music within my own posts to set a specific mood or feeling in place are powerful story-telling elements that many tend to overlook. As far as visual aids go, those are something along the lines of character portraits at the beginning of my posts as well as a location tag to let others know where my characters are. It's very rare I see others do this and I honestly don't understand why, especially in large RPs with dozens of players in different locations.
At the end of the day, I'm a simple person and it's not hard to come up with something that gets be hyped or excited to participate in a particular RP. A lot of the time it'll be a character I create in anticipation that get's be excited to get started and when you compound that with a good idea for a story, it all falls nicely in to place. :)