Are you using the API test kits? Each drop represents one dKH or dGH. Once you've reached your titration endpoint, you've reached your target GH or KH. For the KH test kit, the color should change from blue to yellow. For the GH, it should change from orange to green. If your solution turned yellow or green after one drop, you should have 0-1 dKH/dGH, respectively. Note, the change is usually subtle. If you see a faint change in color, you've reached your endpoint.
Use baking soda to boost your KH:
Arm&Hammer has provided consistent results.
To increase KH (using leveled teaspoons)
1/8 TSP : 6.605gallons = 1dKH
1/4 TSP : 13.21gallons = 1dKH
1/2 TSP : 26.42 gallons = 1dKH
Thanks to wkndracer for the exact amount.