1. I do most of them on my own but I may use some textures from the net as source.

2. https://www.morguefile.com is one place to get free textures.

3. Maya & Photoshop

4. Maybe

5. Good enough resolution for the project (depends on how close shot you're going to render). From digital photos or scanned material I expect them to be clean, evenly lit, no shadows, no highlights and no bad lens distortion (can be fixed up to some point).

6. I am learning it all the time and the better I get at it the more important it becomes.

7. Don't have my bookmarks handy right now :/