Listen to the music contained on the album and use any central theme that is present in the lyrics. Ask your fellow artists or band mates, especially the lyricist, to help you interpret the ideas that are being conveyed in the lyrics.
Speak with the printing company about technical aspects that they need followed. It will require that you have bleed in certain areas and that the file is saved in a specific format such as .tiff. Also, ask it to send you a template so that everything is in order and you know what needs to be done.
Choose a few colors that you think capture the ideas that you wish to present. Using digital editing software like Adobe Photoshop, begin to establish backgrounds and photo placement.
Allow other band mates to view what you have done and edit appropriately, making sure that what you have created incorporates all of the elements agreed upon and are in their correct places. Compare what you have to retail-ready examples.
Send a digital copy to the printing company and review the proof before proceeding. After you approve the proof, and it is ready for print, not much can be done if there are any mistakes.