A simple rule of thumb that should always be obeyed is MAJOR-MAJOR-MINOR. This simple formula will help you avoid those horrible clashing looks you have sported in the past. Probably not your fault as even the best dressed men had to make mistakes to find their own elegant style be that flamboyant or understated. Major, major, minor refers to never having more than two major patterns in the mix between your suit, shirt and tie. Below is are some examples of good and bad co-ordination. Look for what you think the major patterns are. Remember never more than 2 majors but you can do 3 minors, it's just a bit bland sometimes.
Here is a case of 3 majors all together. On there own the patterns are really nice and if any one of the 3 items (suit, shirt or tie) were plain then the look would be fantastic. Instead it looks busy. Great shirt and tie combo but is crying out for a plain charcoal fabric suit rather than a chalk stripe.