3 things that have already been touched on;
1. Temperature, Vinnie suggests getting the temp up to 72 degrees for dryhoppping.
2. Multiple additions, Vinnie also suggests adding smaller amounts of hops over several days. Try mixing varieties.
3. Gelatin, I definitely would NOT add gelatin at the same time as the hops. Gelatin is used as a fining agent after dryhopping. I add gelatin after my final cold crash.
10-14 days primary
3 days cold crash primary
bring temp back up to 72 (36 hours with small space heater)
dry hop 3 oz. of hops every 3 days for a total of 9 days
cold crash 3 days
rack into corney bright tanks (dip tubes have been cut 1/4") hols at 36 degrees 3-5 days
rack into serving kegs and force carbonate.
Many different ways to go, just my .02