I am a home brewing newbie from the UK.

I have made 2 batches so far; my first was a 1 gallon IPA kit using grains which I was relatively happy with for a first attempt; the second was a 40 pints IPA from a tin which whilst drinkable, was disappointing.

I would like to move into adding my own ingredients to a 40 pints kit (yeast, hop, etc.) but don't really know where to start. The reviews for this kit <http://www.wilko.com/cider+beer-brewing/wilko-ipa-brewing-kit-15kg-makes-40-pints/invt/0440627> say that it's a good as a base kit. 

What ingredients would people recommend that I add? Can anyone suggest recipes or a how to guide to follow?

Thanks