Step 1
Here's what you do: leave one-liners for the next ten stories you read and enjoy. No excuses. Just hit that button, and tell the author in one sentence that you liked their fic.

Step 2
Here is what you do: leave two-liners for the next ten stories you read and enjoy. Again, no excuses. Pick one thing you especially liked about a story, and leave that in a comment.

Step 3
Here's what you do: Leave a paragraph for the next ten stories you read and enjoy. No excuses, unless your house is on fire and you really can't stay behind your pc. Give the story some thought and sum up what you enjoyed about it.
Have you left paragraphs to at least ten different stories? Congratulations! You are now a treasured reviewer and every author you leave feedback will love you to bits for it.