Green Thumbed Gardeners: Steve And I Need Your Help!

I've never really been very good with keeping anything alive that requires soil to survive.So really, it's been a minor miracle that I've been able to keep this one plant going for so long. This is Steve. He's my plant. I have no idea what he is (I respect his privacy). I don't know why he's a boy, but he just is. I've had him forever, and he seems to do much better inside than he does outside. I used to have him in the studio, and his.... vines (?) used to be really long and have several leaves on them. Then, there was a period of time where he lived outside. He did not fare so well. He lost a lot of his leaves that way. So I took him back inside, where the cats tried to eat him. So, obviously, I had to take him back here to the stations. I've got him in my office now.

Green thumbers, Steve seems to be okay. I water him regularly, and he gets at least four or five hours of brightish light a day, and then maybe another four of softer light. He's doing better than he was, but... he's not growing very much.  What can I do? Should I transfer him to a different pot? Should I be giving him fertilizer? Should I be trimming him?

HELP ME HELP STEVE!

Please tell me some of your tips to get an indoor plant to grow and flourish, gardening types. Please, share your magic with me, so I can treat Steve a little better.

Plantfully yours,

Behka