Brilliant link there from Ratter, however I wouldn't buy from the RSPB, have you seen their prices?! I have found the cheapest, good quality foods from Wilko. I buy in bulk and have it delivered. For variety I have also been comparing prices on ebay. I get a very good deal on mealworms these days since I found a chap in Barnsley, which is the nearest dealer to me. I use a bank transfer which affords me an extra 5% off and they are delivered much more quickly too.
As Sandy says, apples and cheese will bring back your blackbirds, but I've found that cheese is loved by the robins too.
Don't despair, it took me ages to attract the goldfinches, now I have dozens!