Don’t get caught unprepared if you are asked to send some samples. Even though you could have a site where people can go and see your work, you are going to be asked for more samples. Some times it’s because they want to have something to put in their file, sometimes they just want to see more.
One thing I’ve learned, make samples as you go. Regardless of the end use of any particular piece, I create it at 300 dpi. If it’s going to be used on the web, I reduce it down once it’s finished. I’ve also taken to making a sample page of my work, in the form of a PDF. Everyone you work with should be able to open and look at a PDF.
I keep all the PDFs together, in a samples folder. When someone asks me to send samples, I can pick the ones I want and make a PDF that they can open and page through, rather then having to open a bunch of files.
I keep my samples organized by what they were, my own comics, comics I’ve colored or illustrations. I do page production from time to time, so I have a bunch of PDFs of books I’ve worked on.
This way, I don’t have to worry about making up some samples when asked, I just pull from the ones I have ready. And I’m always adding to my samples.