So, I did technically in the truest sense of the word run a few businesses when I was a kid. Note, as a child they weren't intricate or aimed at making me any real money. They were more like side projects I did to earn a bit of cash because of my upbringing. That said, it did give me a bit of insight into the business world, and currently, as I'm studying culinary arts in college, I'm also looking into business which is a necessary component to actually rise in the industry (a good business backing can take you from line cook to Executive Chef if you're good at what you do). So, that all said, I'll try to offer some advice based on what I've seen you've accomplished thus far:
1. Get a firm grasp of your demographic.
You're starting up a business, and as with any business, if you don't have a demographic to appeal to, you're screwed. One of my little businesses as a kid was making comic books. Now, these weren't professional or anything, I'd just fold paper, staple it, cut it into pages and draw out the same things repeatedly. Were they impressive? Not really. Were they expensive? Not in the slightest, each one was only two quarters. Did they sell well? Yes, because they were aimed at other kids. They thought it was funny and it was simple and easy for them to understand as well as dirt cheap. Plus, it was easy for me to produce, so I could make a few dollars weekly with a new stupid little comic.
Figure out who exactly you want to appeal to. Study the different demographics in your area, as well as different sites if you plan on doing online advertising. Get a feel for where you'd fit in the best, and structure your business to best provide for them.
2. Get a firm grasp of and study your competition.
The video industry isn't exactly a niche industry, so you're going to definitely have competition. Once you have a demographic, look into who is currently providing services for them similar to your own, and get an idea of their skill level as well as their business model. This is always a good starting point as if they're doing successful, you can sort of piggyback off of them. Directly stealing their practices is not approved of, not assuming you'd do that anyways, but it's fair to mention.
Once you have an idea how they're appealing to your demographic, continue structuring yourselves so that you can compete with them, though do not try to outdo them. You'll be financially ruined in no time. A start-up can't hope to beat a set-in business from the get go. If possible, try befriending them. Just because you're competing with one another doesn't mean you have to be enemies. Being on friendly terms can actually lead to them bolstering your business, and vice versa, especially if your particular skill sets or styles aren't the same. This can lead to them recommending clientele to your that they otherwise wouldn't be able to properly satisfy, and the same can be said for you. This can help cement your place in the community.
3. Keep tight records.
Every expense, every payment, every hour of work, everything. Keep records on all actions taken by your business. This is important both in allowing you to make sure you're handling commissions and the like properly and in a timely manner, as well as making sure no money is going missing. A single day skipping work can have heavy costs, or someone stealing your work or paying you less than agreed upon can be hard to handle if you don't have things properly documented and filed. Designing a watermark is also useful in keeping your property from falling into others' hands.
4. Do not ever fully invest in your business.
This one sounds harsh, but you should always try to keep a sizable amount of money for yourself and outside of the business' account. Not to say launder, but as you're partners putting in your own money to make this work, if in fact it doesn't come to fruition, having no rainy day funds will leave you in a bad place. This may sound obvious, but it's still a problem a lot of beginning business owners go through.
5. The client is always right, even if they're horribly wrong.
This one tends to be tricky. When working with a client, even if what they're saying doesn't agree with you, keep yourself friendly and professional. In the case of when I used to sell ice pops (the ghetto kind where you put kool-aid in ice cube those red plastic cups and sell them to kids on a popsicle stick for a dollar in the summer), I only sold two flavors. Some kids wanted more flavors, or when I ran out, they'd demand I give them the sold out flavor. Obviously this didn't work, so what was I to do? Keep a smile and tell them "I'm sorry but I just can't do that." Sometimes I lost out on customers, but it gave me a good reputation and earned me others. If you can help it, give them what they want or kindly explain why you can't. If you're friends with other businesses, you can even recommend them to them, strengthening relations (killing several birds at once).
6. Keep up with the times.
Always keep up with industry trends. People flock to trends like you wouldn't believe. It's crazy, it's sad, and it's exploitable. Also, don't be afraid to look into disasters, tragedies, etc. In the video industry, charity organizations are some pretty big clientele. Sometimes, you won't get paid. But a quality product with one will land you a lot of good publicity and reputation, and can easily lead to contracted business or simply clientele with more expenditure.
7. Schedules, schedules, schedules.
DO. NOT. TAKE. TASKS. WITH. SHORT. DEADLINES.
Any time something has a short deadline, there's a good chance you're going to have to sacrifice quality. Unless you are definitively certain you can do it, I recommend heavily against anything with a seriously short deadline. This is especially true with contracted work as they pretty much own your ass.
Hope some, if not all, of this advice can help you out.
