If you are having difficulty holding your camera straight, purchase a tripod. A tripod will go a long way in helping to keep your camera in place, so you can focus on other variables other than balance. Tripods work great if you are in the wilderness or on an uneven terrain.
When working around subjects that are moving a lot or are totally in action, you need to focus on capturing the moments by keeping your trigger down. These kinds of moments can not be recreated and there are no do-overs. Keep your eye on the areas at all times and keep shooting.
This is a video tutorial about how to make a portfolio optimized for an iPad or other tablet device.