Many recreational boaters in smaller boats don't consider it important to have charts onboard. Bad idea, even if you are just operating on your local lake. Even if you are not yet an expert navigator, knowing the basics of chart reading can be invaluable on large bodies of water. A chart onboard allows you to compare what you are seeing with what you should be seeing and can help you keep your bearings.
Nautical charts are different from maps in that they specifically depict water areas, while maps concentrate on land area, roads, landmarks, etc. Land areas and features on charts are sketchy and are noted only for their interest to the boater. Unlike maps, the nautical chart conveys much information specifically designed to assist in safely navigating the area that the chart covers.
Study your chart thoroughly
Look at the position from which you will start and visually follow along the course you wish to take
Look for "notes" - water depths, obstructions (especially under water), bridges, power lines or any other unusual items that may be a hazard to your progress
Make a note of each of these on a separate piece of paper
Make note of all buoys and markers you may pass in the order they will appear. This will give you a documented picture of your route and what you should expect to see without having to continually try to find a small marker on the chart
Look for visual objects featured on your chart that you should be able to observe and identify to confirm your position
Always check the weather before departing