Agreed, genetics play the most important role in development of muscles. Agreed, compound exercise are the best exercises as they target many muscle groups. Unfortunately there are many, and I can be included in this over my 11 years of lifting, working the biceps by isolating them is something we try to do to improve them.
I've always enjoyed Concentration Curls that have helped me lift the most weight.

Dumbbell Alternate Curls I've also enjoyed.

And of course Preacher Curls.

No matter what you choose find something you like to do as that will make a difference as well. If you like doing them then you will work hard at them.
To be honest I hate bicep work and rank that up in my top two muscle I hate to work. I tend to focus more on my triceps to get a bigger looking arm.