Mr. Bossy Pants
Clients will either be awesome or very bossy and might even fire you for "incompetence." Working with clients is a great way to make money, but be careful. That client could be a dictator.
It is not that all clients are bad, but I am sure that they are out there. I have never really worked with a difficult client before. All of my clients have been very good. Basically, I don't have much to offer here, but let me enlighten you.
Common Sense
Work with client(s) to see what they want, be fair on pricing, and always deliver on time. Now pricing can be a difficult thing. You don't want to ask for too much, but not too little either. Know what equipment and experience you have. If you have amateurish equipment and very little experience, go low or even free for your video projects.
Angry Client
Again, I have never worked with a very upset client before. However, I have seen and heard about angry clients. Here is my advice: professionalism. Don't be angry back. Apologize, forgive, and move on.