It is very easy to get VAT back for purchases made in shops which are connected to the 'GlobalRefund' system. The logo is displayed in the shop or you can ask for 'GlobalRefund Check'.

The form must be completed and stamped by the shop with the receipt stapled. You'll have to go to customs for the stamps. Then go to the GlobalRefund office at the airport and you'll get the VAT back, minus a handling fee.

Another system in Germany are the green forms "Ausfuhr- und Abnehmerbescheinigung für Umsatzsteuerzwecke bei Ausfuhren im nichtkommerziellen Reiseverkehr". Problem is that you have to 'export' the purchases and document it with a stamp from customs, but to receive the VAT, you'll have to reenter the country (e.g. on your next trip) and go to exactly the same shop where you purchased the stuff.

Hope this helps!

This should do the trick.