I believe a number of larger airlines used to run courses for nervous passengers, starting from an introduction to the cabin and working up to a short flight, I would imagine it would also cover checking in and making your way through to the boarding gate.
It's possible it may be of help to you as it might give you some idea of what to expect when you get to the airport, rather than have to cope with the whole thing from a cold start.
If you're within comfortable travelling distance of a major airport it might be worth phoning some of the larger airlines to see if they can help with this.
Hope you have a safe journey.