It might be fair to say that all design is manipulative on some level, seeking to influence people's attention, thoughts, emotions, and behaviors. See these 5 Design Tricks Facebook Uses To Affect Your Privacy Decisions.
Attention designers: if you don't want to compete for jobs with college students, overseas labor, and someone's cousin who will "do it for free," then it's time to think of yourself as business person first and an artist second.
As a graphic designer or digital artist, the opportunities you get will be largely dependent on your portfolio. In fact, your portfolio will likely be the deciding factor for employers or clients as to whether they hire you or not.
Graphic Designers have to be very detail-oriented and often are required to wear more than one hat at a time. This can lead to simple mistakes and oversights. Here are some common graphic design mistakes and how to avoid them.