How to help a hyperactive child

Unfortunately, you can't just get that from a vending machine. That's something you have to earn, and it's hard-won. It takes years. I'm not saying that to discourage you. I'm just pointing out that, yes, it really is as hard as it feels. Hyperactive children are challenging. Cut yourself some slack. You aren't failing. You're probably already better at it than most people. You don't need to be perfect.

Cognitive Behavioral Therapy is extremely beneficial for the parents of children with ADHD. The more you understand, the better you will be at managing your child's behavior and the more happy and successful your child will be. Go to therapy regularly. Tell the therapist that you want help in understanding your child and being a better parent/caregiver. This is not a sign of failure; this is a sign that you are determined to be successful. Therapy. Regularly. Even if you need to get a babysitter.

A few tips that have worked for me:

Redirect, don't try to control. A hyperactive child is like a raging river. It is easier to divert the flow of a river than to dam it up. Redirect your child toward productive, positive, or nonharmful activities. Instead of telling them to sit down or be quiet, tell them to do 50 jumping jacks, take deep breaths, speak in a whisper. You can't bottle a hurricane, so don't even try.
Instead of yelling for attention, quietly walk over to your child, put your hand on their upper back, and wait for them to give you attention. Speak calmly, quietly, and concisely.
Have frequent exercise breaks--at least three times a day.
Take a breather. Schedule time for yourself in advance. Don't wait until you're exasperated. Plan ahead and don't skip your “me time"--even if you just use it to nap or to sit and do nothing for an hour. Unstructured time is essential to proper brain functioning and mental health. This is especially important if you are a stay-at-home or single parent.
Walk away when you need to. “Mommy time-outs" are ok.
Don't buy new furniture or home furnishings that you'll worry about keeping clean. Your child will be grown before you know it and you can have nice things then.
Forget having a clean house. Meet friends at restaurants for the next several years. It's fine. Really.
Lower your standards for superficial things. In the long run, appearances don't matter. Invest in what's meaningful, what makes you happy. Feed your soul.