Organic matter is temporary and needs to be added every year. Sand is permanent.

The problem with sand is that it takes a lot to help. If you don't add enough, you can actually make it much worse. The extension service recommends against sand for that reason. If you add too little sand, it will set up like concrete (technically more like adobe, but it will be rock hard and much worse than what you have now).

If you want to add sand, just make sure you add enough. Also, make sure it's coarse sand, not playground sand.

http://www.vegenag.com/2009/03/expanding-the-garden/

Basically you want to add sand and peat moss to help the texture and a balanced fertilizer to help the soil content and pH. Continue to improve the soil every year by adding organics like grass clippings, dead vege plants etc.

For more information on the fertilizer go to:

http://www.vegenag.com/2009/03/fertilizer-basics/