Take notes while reading. If you "read" something, but don't know what you read, you didn't really complete your reading homework. Define unknown words, research the unfamiliar in the work - this is how you improve reading comprehension.
"Chunk" your assignments; don't procrastinate and try to do everything the night before it's due! (think about practices/extracurricular meetings, needing help, having a life, etc.)
Know that writing is never done, it is just due; writing is a process and all writing should always be revised. Write rough drafts before final drafts for all assignments and have someone peer edit your work.
Ask for help when you need it. Like Oprah says, "You get in life what you have the courage to ask for." If you are complaining about not getting help, it's your fault for sitting around complaining.
Turn in ALL assignments, big and small; take advantage of extra credit even if you "don't need it."
USE a computer intelligently and efficiently; Technology is your friend and in order to live and grow in the 21st century you MUST be able to do these things even if you don't like it.