Do

Do be creative. Let your imagination free to create unique and unusual designs.

Do research your thoughts or ideas. Whatever you are working on, make sure you research the trends and see what others have done with the same ideas.

Do look for inspiration. When preparing a design, look online for other works that will inspire you.

Do find your own style, and apply it to your work. At some point all designers find a style, and it can be viewed as a signature of your work.

Do seek new methods and techniques. Always look for new ways to add effects, or pizzazz, to your designs, or ways to make things easier.

Do know when to keep things simple, and when to go wild. Sometimes a design needs to maintain some level of simplicity. Know when to recognize these instances.

Do advertise your work whenever possible

Do join social networking sites like Facebook and Twitter.

Do feel confident in your creation. It's OK to be proud of your work.

Do ask other designers about their own path to success, techniques, or advice.

Do make sure that the place, website, or portfolio that displays your work, is professional, and a great representation of your work.

Do remember end usability when creating your designs. Remember that your design could be used on many different mediums, and your design may need to be scalable.

Do Not

Do Not go overboard on effects such as drop shadows, glows, bevels, blurs, etc....

Do Not use rainbow gradients and expect them to be taken seriously.

Do Not take negative criticism badly. You will receive from many people, even if it's your best work. Some people will think they know what they are talking about, and some will.

Do Not ask multiple people what they think about your design. If you ask 15 people about what they think, you will receive 15 different responses. This only leads to confusion. Only ask those whose opinions you truly respect.

Do Not complicate your designs. Know the different between busy, and creative.

Do Not pass on any opportunity to display your work.

Do Not disrespect anyone in public or in general. Always keep your composure when dealing with clients.

Do Not under price your work, as many people believe you get what you pay for, and if your prices are too low, they will think the service is of lower quality. It also lowers the value of a graphic designer in general.

Do Not spam peoples emails. It's OK to do a little email marketing, but be sure that you are offering them something they could really use. Be smart.

Do Not forget about Skilled Graphics when you share this with others ;)