1. Don't yell your dogs name. It can hear 300% better than humans, yelling will only scare it off.
2. Don't make noise when searching by foot, remain quiet while walking. The dog will know you are near long before you'll ever see it.
3. Don't hurry when searching. Make intentional stops to look around for movement. If you don't see your dog , try making a quiet whistle sound - the concept is to create a movement by the dog, not to attract it to you (if you live in a densely populated area you can try this at night when it's quieter).
4. Don't solicit help from friends without being clear on what their task is and be sure to inform them of 1, 2, and 3 above.
5. Don't put your personal safety at risk by entering unsavory areas, crossing freeways, ascending/descending terrain in the dark and so forth. Have someone with you as deemed necessary.
6. Don't use online services, especially robo-call agencies unless you have fully vetted them out. The vast majority of these are scams and will take your money with no actions taken (some are valid, just be sure to check first).
7. Don't chase or run after your dog if you see it ! The dog should always be made to come to you. Get down on the ground (literally) and using your peripheral vision continue to observe you dog. Get your treats out and make sure your dogs sees them. Put a couple near you and pretend to eat them. When your dog gets close enough to you to acquire your scent, it should then approach you without hesitation.
8. Don't give up. Persistence is key to a successful recovery of your dog.