I recently wrote a book about training and showing in halter obstacle that includes sidepassing and pivoting and much more that you might find helpful. It is called Training Miniature Peformance Horses: A Comprehensive Guide to Hunter, Jumper, and Halter Obstacle.
Once a horse learns how to pivot through verbal commands, I start to use the verbal commands less such that the horse learns to move off my body language alone. After practicing a lot, you will no longer need to kiss or cluck and the horse will follow just your body lanuage. This is very important if you want to compete. You are a awarded higher level of difficulty for minimal cues.
As for sidepassing, it is GREAT that you have taught the horse to pivot on the front and rear legs. That is very, very important. Now it will be much easier to get him to sidepass. Sidepassing is one of the harder things to teach your horse, but since he knows how to pivot you are already on the right track. To start off, give the command you plan to use for sidepassing and ask him to pivot 3 steps keeping his rear hoof in place and just moving the front hoof those 3 steps. Stop him and then ask him to pivot on his front and move his rear 3 steps. Reward him when he has done this simple task. Repeat this over and over slowly adding more 3 steps intervals at a time. The sidepass will look choppy at first, but that is okay! With a little practice he will be sidepassing as fast as you can walk! Just like Quaters said, don't worry about side-passing over a rail. Just get the sidepass down first and then you can practice sidepassing over poles and flower pots and such.
Good luck! :aktion033: If you have any questions feel free to PM!