Its all about generating power to raise all the weight up the hill, that means getting stronger. On shorter hills of no more than about 90 seconds of climbing I go anaerobic and hammer like nobodys' business, then almost pass out gasping on the descent.

On longer climbs its like kk4df said, do a weekly session of repeats and over time you'll own those climbs. I make it a point to plan hillier routes when commuting somewhere, provided I have the time. The more you climb the better you'll get.