First of all, if you can stop flying great. If not, consider every flight carefully. Personally, I will no longer go on a short haul flight. That means all trips to the continent have to be by ferry or train. I have family and friends in Australia and this makes it difficult for me. I haven't been for 6 years and am planning on going next year. This one return flight will produce more carbon dioxide emissions than I should emit in 5 years. With my partner I am well on my way to having already done or doing the things on the list below but travelling to Australia makes it extra difficult for us to meet our long term targets.
Personal actions you can take to reduce your own greenhouse gas emissions in order of priority, from top to bottom based on benefit versus effort or cost.