i think you theoretically only need one pr3 backlink to be pr3. there's a chart on google if you want to check. btw i sell permanent pr4 backlink for $30 - that's a sure way to get pr3 by next update
The only way I can think of is: -Directory -Link exchange -Buy Link -Get list on dmoz (very effective, almost guarantee atleast PR2 on next update..xD)
Here are my best tips, I am a n00b and my site got a PR3 and its just 3 months old. I am still in shock: 1. Social Bookmark with high PR sites 2. Post in relevant forums 3. Write Articles with an edge that are funny or controversial 4. Submit site & directory only the good ones, forget the "I will post to 50,000 directories for $5" 5. Set up a Squidoo lens Oh and do it all slowly and regularly. Jack
If your site has 200 pages or more, and your homepage is being linked to often in your architecture, it won't be hard getting a PR 2 or 3 nowadays. The harder PR upgrade falls into PR 5-7 where age of the links and authorities of the link are being processed
Getting quality of inbound link helps. Here are some of the things you need to do if you want to get high PR: submit your site to directories do forum posting comments on blogs submit your articles to article directories, classified ads, press release do social bookmarking and networking