Acessories are all the little things that help you explain the story. Things like lines that indicate motion(as with the balls above). There are hundreds of acessoies in cartooning and you will undoubtedly devise a hundred more. Here is a small list of favored acessories.
Words can add alot to your cartoon. They can add sound effects. They can tell how your character feels. They can explain the scene when a picture can't. See the image at the top of this page. With out the sign that says "World class juggler championship" this cartoon wouldn't make much sense.
QuincyPaint is a great tool for createing various text. Make sure you read the QuincyPaint help file. Its has a text tutorial. You need to fully understand all of the tools in QuincyPaint to make cool text(especially the photo filters and using layers). The outline tool is particularly handy for text as well. Experiment a lot with QuincyPaint to see its true power.