Basic considerations for a textbook:

•  Level of class  (developmental, on-level, honors)
•  Price (and this should not be too high, regardless of your neighborhood)
• Reading level (It can exceed their grasp, but it shouldn’t do that by much.)
• Complexity (Is it really going to be usable?)

Other considerations:

• Visual (pretty colors, pretty pictures)
• Graphical (pretty diagrams, graphs, tables)
• Age (modern)
• Holes in your enthusiasm (It should fill those.)
• Additions not readily available on the internet  (It should give the students something they can’t get for free.)

Things you do want:

• Accuracy  (No major errors in fact or theory.)
• Relevance (Ought to work well for your class and not have to be worked around.)
• Readability (Has to be at a level the students can get.)
• Accessibility  (Information should be chunked, for easier understanding.)