Balancing flavor and bitterness

Are there any good tips on best balancing flavoring and buttering hops for an IPA? I made one that seems a lot more bitter than flavorful. I know that IPA's are supposed to be more bitter. I boiled my flavoring hops (chinook) which is around 13%, for 50 minutes. I added my flavoring hops, which were around 11 %, for the last 10 minutes of the boil. Any advice would be greatly appreciated.

Flavoring hops are generally added from 30 min to 15 min of the boil. Aroma hops from 15 min to 0 min. To balance bitterness and flavor, start to look at the ratio of hops used through out the process. AA% play the role of bitterness and can be calculated, but flavor and aroma do not depend on AA%, they come from the type of hop and quantity used. Reference other recipes, and experiment, experiment, experiment. Hop storage conditions also play a role, as old stale hops will not give much flavor or aroma. It gets much more complex than this, but its a start.

I used a brewers best IPA recipe. It called for 3.5 oz. bittering and added.5 ounce aroma at 55 into
My boil. I used 4 ounce bittering and 1 ounce aroma. I also used an extra .5 lbs of liquid malt. Was this too much. Bittering?

That depend on many factors. What was the size of your boil/batch, what was your target og, and did you do any late extract additions? Do you have access to software such as Beersmith? If you plug in your recipe it will give you your estimated IBUs. In addition it will tell you via gu:bu how balanced your beer will be. A ratio of .5 is balanced, over is leaning toward bitter and under is sweeter. For an IPA you definately want to be over.

I have ibrew for my phone. I think I can do it in there too?

Cant remember which book it was, either "designing great beers" or one of charlies. A neat thing to keep in mind when creating a recipe and making adjustments is what they refer to as the "bitterness unit to gravity unit ratio" or BU:GU.