Sure. Here are some thing I've learned:

    -- Stuff takes more time than you think.
    -- Get everything in writing.
    -- Make sure you are legally clear to build a business on the side.
    -- Schedule and plan in advance so you dont waste time.
    -- Schedule free time so you can relax.
    -- Remember to eat well/exercise. Good health is important.
    -- Dont talk about your business to your co-workers/boss. Tell them you are taking a pilates class or whatever kids these days do.
    -- A business is 99% business and .5% coding with a .5% margin of error.
    -- Remember to smile and listen. :)
    -- Hire contractors instead of employees. Cheaper, less hassle.
    -- Get a lawyer and acocuntant involved ASAP.