What should I check first in my post crawl reports?

Check the Crawl Overview to see the crawl status. Did it complete? Did it hit the time limit? Was it stopped unexpectedly?
Check the Seeds tab to make sure all your seeds were crawled or if there were any robots.txt blocks or other issues preventing sites from being crawled.
In your Seeds or Hosts report , check to see if some seeds or hosts were partially blocked by robots.txt.
In the Seeds tab, make sure there are no big surprises–did a seed that you thought was quite small archive a considerable amount of data or docs?
Use the Archives link in the top navigation bar to browse your content in Wayback. As they say, "a picture is worth a thousand words," so browsing the look and feel of your results can help verify whether or not you have a complete and functional archive of a website.