Please let me know any comments, advice or personal experience. thank you 

I read a lot of books and threads regarding the importance of Due Dilligence for the apartment buildings.After the proptery is under contact,I will definitely do the detail due dilligence in person and with propterty manager or contractor.But still I have the concern that before I put the proptery under contract,if I am in long distance or out of state,how could I do the due dilligence to do the pre-acqucition analysis (repostition chance,how much value can de added)?

I encourage you to stay involved in the community and see where BP will lead you.Real estate is a rewarding journey if you can put all the pieces together.  

Here are some recommendations for you:Find and connect with other BP members that are in your area: http://www.biggerpockets.com/meetSet up keyword alerts to be notified of the topics that interest you: http://www.biggerpockets.com/alertsRead Beginner’s Guide: http://www.biggerpockets.com/real-estate-investingCheck out BP Podcasts: http://www.biggerpockets.com/renewsblog/category/podcast/If you wish to tag someone in the conversation on the forum, type @ followed by their name and then select the name of that person which should appear below the comments box.

My own personal opinion is that a realtor needs to be on the team, wether that's you or your partner, or someone with whom you have built a relationship and who has an expectation of getting paid through multiple deals.

I don't like this term personally and It's likely missused often.

When I started investing, I was under the assumption that I wanted to make my realtor a very wealthy person!

You can find all kinds of contracts online, but any seasoned investor (and real estate agent) would strongly encourage you to have it reviewed by an attorney prior to use.Oftentimes, off the shelve documents work fine... until something goes wrong and then all bets are off.

In this world of too much information and the need for attention to detail I personally like getting as much information as I can on any given subject; especially if it might impact or influence my personal financial situation which this does. 

My personal opinion is that QB and the like are good for very big companies with a complicated portfolio and your accountant who can just import the data and saving him work.