Here is a good starting place:
http://www.charith.gunasekara.web-sphere.co.uk/2010/05/readmore-panel-like-facebook-wall.html[
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Beyond this, you are going to need to figure out what you really want. Lay out your requirements (what the site should do). Then break them down into logical chunks. For instance, first you need to have data so one of your chunks should be that you develop the database structure. From there, you could get the overall page layout done. Next, you could work on displaying a list of items on the page. Then turn those items into posts. Keep going like this, doing a little bit at a time until you get the whole process complete. Ask a new question if you get stuck on a piece.