Prior to personal carbon offsetting, reducing the size of your personal carbon footprint is an important first step. Halfway down this VERY informative study by the University of Michigan is a list of ways to reduce your carbon footprint. Following this, are links to three different footprint calculators that can give you a ‘picture’ of the size of your current footprint.
We suggest that if ready to purchase carbon offsets you hold off for a few weeks. Renewable Juneau has a project in store that may be of interest to you!
Source: Carbon Footprint Factsheet | Center for Sustainable Systems