Today's topic has nothing to do with music, but could have a greater impact on your career than your talent will. Your attitude towards those that hire you might not make your reputation, but it can ruin it. Here is a rather important concept to keep in mind ......
Your client is not the enemy.
As a composer for TV, film, or advertising, you will be creating music for people that may have a very difficult time articulating what they want. Uneducated suggestions may be offered. Perhaps extensive hand holding must be provided. Much of your time could be spent creating examples of what you believe won't work, simply to prove to everyone what doesn't work. If this process has you researching ways to torture your clients, that negativity will create a wedge between you both. "Why won't they just listen to me??? I toured with Bowie, man!!!" .... no one cares. You've been hired as a partner in this project, not a condescending expert. You want to be remembered as the knowledgeable guide that helped navigate the jungle, not as the overgrown vegetation they had to hack through.
This same principle applies if you are an orchestrator. Perhaps the composer has never worked with an orchestra and is beyond nervous. You want to explain the process, not be dismissive of suggestions, and put them at ease. Instrumentalists face the same challenges. Every horn player I have ever worked with has stories about the session with some clueless guy asking him to do the impossible. You can be the cause of their musical PTSD, or be the hero that contributed to some great music. The trash heap of promising careers is overflowing with bad attitudes. Those with great success have embraced this reality, and strive to make the experience as positive as possible.