Read the dilution sticky, quit exercising, eat plenty of good beef, and do some more home testing. Test your first piss of the day. If you can get a negative on that you're probably good for your official test. Even then, you wouldn't be going wrong to do a light dilution and use gatorade in place of water to keep your specific gravity in the correct range. Make sure you don't give them your first urine of the day and when you give the sample make sure you take it from midstream, iow, drop some into the toilet, then give the sample. Good luck and let us know how it goes.