I don't see you site in sandbox, i see a lot of links from your site. Tested with site:sitename.com. If you want higher pr, then i can only tell you to make seo.
There is too much competition on a perticular i checked my site with seomoz but i was ranked 5 to 18 how can that be improved
How new is your site? If you build too many links in a short time to a new site, you could land your site in the sandbox. You have to build slowly when the site is new.
It's depend on why you got sandbox. First if you're doing any unusual activity(any black hat strategy) then stop this like if your site having duplicate content then change it & send reconsideration request to google.
I do not write duplicate content yes i do use reference quoto for linking to other article and yes i share ideas mix them with my own and write them if that unfair i donot care it donot apply to my site about a year old i shifted to new domain this february. Beside directory give backlink their own ways