I have this domain for quite some time. I have made some posts. My friend suggests me that making some good posts and getting a page rank will get me a lot of money. Should I do that or sell it right away?
Hire a full time article writer, get them to write 4 articles every day, hire him/her for 1 hour and pay $5/hour. Then just post 4 articles per day, get some adsense and your good to go.
Your friend needs marketing experience if that's his/her advice. Nobody "makes a lot of money" blogging unless they work their ass off, for at least a year or two, and has a lot of knowledge about the subject matter. I would suggest finding another domain name, considering that yours has "the" in it, and you'll be at the mercy of the owner of "gizmoblog.com" for the life of your site...not to mention, potential trademark issues.
If you have no serious intentions with the domain, it is unlikely you will be able to get good Google rankings. For this reason, I would advise you not to waste any time on it and just sell it.
You got a good sounding name and it surely has good potential to work for you well... if you put in good effort behind it. Blogging is a serious business and you have to put in consistent effort... for it to bear fruit for you. Without any development effort behind this name... I doubt if it would fetch you 'lot of money'! Regards, RightMan