Even then, you must have a firm command of all aspects of the game to even touch them. In general, try to collect anti-dragon equipment like armor, swords, and the like. Dragons have terribly high magic resistance, so you must cast spells that lower their abilities to block your spells. Once that is done, try to stick to damage spells that are difficult or impossible to resist. Some great choices are magic missile and Abi Dalzim's horrid wilting.
Nothing is sweeter than seeing a powerful dragon fall in the first ten seconds.
Otherwise, defend yourself with any and all magical defenses you have. A great weapon to combat dragons with is a bow with arrows of biting. Also, try to increase magic resistance and any spell immunities. Dragons will cast wicked spells that include a swipe of all characters that sends them flying in all directions. Lastly, try to remember that the different colored dragons will be resistant to the element of their color.