I brew all-grain, but the principles are the same. Keep your malt bill simple, mostly pale extract, maybe a touch of light crystal, and some refined sugar if you are pushing the gravity up. Go with plenty of your favorite hop varieties (I like a combo of Simcoe, Amarillo, and Columbus), especially near the end of the boil and for dry hop (I've gone as high as 5 oz at flameout and 6 oz for dry hop). Some gypsum to boost the sulfate content of your water to ~150-200 ppm can make the bitterness crisper as well. Ferment with a clean ale yeast like 1056/001, making sure to keep the wort temp down in the 60s.
Oxygen is the enemy of hoppy beers, so after you aerate for fermentation do your best to keep air away from the beer. If you have a kegging system flush everything with CO2 when you move the wort after fermentation and force carb (I did 3 oz of hops for a warm secondary, then 3 more in the keg as it carbed cold). Once the beer is carbed keep it as cold as you can, heat also destroys hop aroma.
Hope that helps, I think IPAs are more about the technique than the recipe specifics.