Chapter 3 in the book we use for class (2nd link on the bottom of the page) discusses how to avoid legal hassles and one of those is plagiarism. There are many ways to avoid plagiarism.
One huge one is to attribute everything that is not yours. Plagiarism is not just using someones words. It can also be things like photos, ideas, music, and pretty much anything that is created.
If you want to use a photo or logo or artwork make sure that you have the right to use it. Many people will copyright their photos, and copyright infringement is not something you want to be accused of, especially if it’s on accident.
Be careful about uploading or downloading things to/from the internet.
If you are writing a paper then you can go to turnitin.com and submit your paper just to see if it shows that you copied something directly from another persons words. If it does, put it in quotes and cite it.
A few from Purdue:
SO, go out there write papers, take photos, and create! Just make sure if you are using anything that is someone elses that you give them some credit, they worked hard on it, you would probably want someone to give you some credit too.