"I'm a high school senior who has trouble following directions unless every step is listed. Unfortunately, teachers rarely do this. Any suggestions?"
Stay after class to talk to each teacher. Say, "I always do better when you list all the steps. Could you remind me what to do after finishing _ _?" This will show your teachers that you're aware of your needs and that you're advocating for yourself—and make them more inclined to work with you.
If you have an IEP or a 504 Plan, see that it specifies step-by-step instructions in class and for homework assignments as an accommodation. Then say something like, "I brought a copy of my 504 Plan today, so we can review it before the test. Is there any other way you think I should be preparing? I really appreciate your help."
If you ever forget to do this and need to figure out how to do a homework assignment, approach it like a puzzle. Read the directions, take a deep breath, and say to yourself, "OK, now it's my turn to try to figure out what's missing. Let's see what it could be." ADD brains love a challenge.