I have kept and bred a ton of varieties of fish over the years and in my opinion, discus are just not a fish for the beginning aquarist. It is far easier to learn on a tank full of guppies than a tank full of expensive discus. Get the basics of keeping a tank and keeping fish down before jumping into the discus.
To be successful with discus you need to educate yourself on their requirements and provide them with what they need to thrive and be healthy. That is no different than for any other fish. If you go in to keeping discus thinking you can do it your way and not the way that's good for them, you will not be successful. For instance thinking you don't have to keep the tank temperature above 78. That is no different than for any other fish. Start with healthy, disease-free stock and you're already on your way to success. That is no different than for any other fish. Feed your young, growing babies and juvenile discus an excellent fortified diet and feed them more often while they are rapidly growing to ensure strong, healthy fish. That is no different than for any other fish. When you feed the growing discus more frequently, it will result in more chance of leftover food in the tank and the discus will produce more waste themselves, resulting in the need for frequent water changes. That is no different than for any other fish. With frequent feedings of young growing discus, maintenance is easier acomplished and more thorough in a bare-bottom tank. That is no different than for any other fish.
So this is just a brief example of comparison of discus keeping to other fishkeeping, including angels. Quite a lot of "That is no different than for any other fish." Break some of these basic fishkeeping requirements and you've broken your own success link. And these are basic requirements for many, many types of fish.