Copyright law can be confusing. Which works can you use and how can they be used? Copyright law restricts your access to other people's work and restricts other people’s access to your work.
If you allow others to make changes to your work, you also need to think about whether or not you will require them to use the same license as you (SA). Share-Alike ensures that your work is always used under the terms you want, even after many generations of copies and derivatives
Do you want to allow others to make changes (derivatives) to your work without having to ask? Non-Derivative (ND) Prohibiting derivatives might prevent others from making something really cool out of your original. But, this also means they may not use your work in a way you disagree with.
Do you want to allow other people to sell or make money off of your creation without having to ask? Prohibiting people from using your work commercially may limit how widely it is spread. This also means that no one can make any money from your work without your permission. You can work out individual arrangements for commercial use so that you can get paid when others profit from your creation.
Many services, including Flickr, SoundCloud, Google, Bing, and Vimeo, provide their own advanced search feature, making the search for CC licensed works quick and easy.