Redirects Do Not Lose PageRank
Google say there is no PageRank loss for 301 or 302 redirects.
Don’t Use Nofollow for PageRank Sculpting
John says it’s OK to use nofollow internally to prevent things like a calendar being crawled, but recommends against it for PageRank sculpting and says it won’t change anything.
Googlebot Requires a Consistent Response for Different User Agents
You need to provide the same response for all users based in the US, including Googlebot, or the content might not be indexed.
PageRank to 404 Pages is Lost
Any PageRank acquired for pages which return a 404 is lost.
New Pages Are Ranked Higher to Gather Signals
New pages are sometimes shown in search results and given an opportunity to perform, which may change when they gain more ranking signals.
Noindex Pages Won’t Be Crawled Eventually
If a page is Noindex for a long time, Google may stop crawling the page so it can’t pass PageRank.
Google Will Choose a Duplicate Page with the Shortest URL
URL paths doesn’t affect PageRank. However if there are 2 pages which are a duplicate, they will prefer the shorter URL.
Many to One 302 Redirects Will Be Treated as 404
URLs which are 302 to the home page on any large scale will probably be treated like a 404 and dropped from the index, and pagerank won’t be passed.
Multiple Redirects Doesn’t Lose PageRank
Whilst describing how 301 and 302s are indexed, John seems to suggest that a redirect chain doesn’t pass less PageRank than a single redirect.