Congrats, videos are very fun!
Before you get into all the settings and such, you first kind of have to figure out what you're shooting and what you plan to do with the footage you captured.
For example, if you're aiming for something more cinematic looking, you'll probably want to go for 24p and a 1/50 shutter to get that movie look. However, if in the middle of your video you have your character do something like watch a home movie, then you probably want to shoot that 'home movie' with a faster shutter speed to emulate the choppy look of a cheap camcorder. What you want your footage to look like is what determines your settings.
As to HenrikBC's link to the picture style, that one is hard for me to recommend. I certainly do shoot flat, but I also spend tons of time in post. The purpose of a flat picture style is to not "bake" certain camera settings into the footage to get it as neutral as possible. This assumes that you'll spend time to add back in the contrast, saturation, etc. If you won't be doing post production, then the flat style probably won't suit you since the saturation will be gone.
It's like people who shoot in raw, but never do anything with it, just convert to JPG and upload. At that point, just shoot in JPG and get your sharpening, saturation, and contrast in camera and be done with it.
As for tips for focusing: seriously, the only tip is to practice. There is no holy grail for focusing tips. You can study all the great shots and try to emulate their look, but if you don't practice, you'll be focus hunting worse than a contrast detection autofocus in a cave.
For example, I just finished a wedding on Saturday thinking I did alright given the lighting and organizational constraints (as in, no organization. They were all over the place doing things last minute and I scrambled around trying to capture everything). I was reviewing the footage on Monday and I lost some nice shots because of focus. There's this one where I had the bride's back in frame and thought I had the focus on her reflection as she checked out her makeup. All I had in focus? Not the bride's back, not her reflection, but just the freaking mirror! Major fail. I need to focus on focusing.
Anyways, tangent aside, just go out, shoot, edit, have fun. It's the best way to learn.