Hill climbing has SO many variables, I have just changed the gearing on my bike to help with steep hill's 20-25% gradient.
Ultimately hill climbing comes down to Gearing, Weight,Technique and mind over matter!
If the bike isnt geared for hills you will struggle! I have 2 road bikes one with a Compact chainring 34/50 and 12/27 cassette, and one with a standard 39/52 and a 13/27 cassette - The 34/50, 12/27 combination wins on all hills...
The heavier you and your bike is the harder work the hill will be, Its all about power to weight, you have a finite amount of power, if you are lighter that power goes further and faster!!
Technique, We are all different, I push to high a gear at to low a cadence all of the time, this makes my technique of hill climbing all about raw power, I climb the hills and maintain a reasonable speed (About 5 mph on a 1:6 gradient), Some people I have cycled with have less power but a better technique, they stand and sprint - Who is better? I get to the top and carry on going, they get to the top and have a higher Heart Rate.. It depends what you are comfortable at :-)
The best way at getting more comfortable with hills is to find the steepest hills you can and simply ride em :-) - They get easier and what you once thought of as a hill you will find is nothing more than a slight bump in the road :-)
Good Luck John
http://johns-cycle-diary.blogspot.com/