Train the Right Way
Like most things there is a right way and many wrong ways to sidemount. Ever seen pictures of sidemount divers with their cylinders out of alignment? With hoses hanging and other dangles/entanglement hazards? Or, struggling with their equipment getting in or out of the water?
The key to sidemount diving is the correct equipment, setup and training on sidemount techniques. By investing in training with the right instructor you can save yourself months or even years of frustration using trial and error to perfect your sidemount diving. I can tell you from personal experience, that learning from online forums and videos is not a substitute for training and personal support from a suitably experienced and qualified sidemount specialist instructor.