Sure! Before starting any artwork, make sure that your image resolution is high. I usually use 300 pixels/inch as my resolution. When you're saving it, go to File> Save for Web & Devices> Change the file format to JPEG, choose maximum and then change the quality to 100 then click save. If it doesn't allow you to save your file due to its big size, you could save it with Adobe Illustrator. First thing you need to do is save your artwork in PSD format. Then open Adobe Illustrator, go to File> Place> Click the PSD format file then click place. Now look at the tools and look for the Artboard Tool (Shift+O), then click the image/file twice using this tool. After that save the file using the same process I said a while ago. That's it! I hope I was able to help you.