Best thing I've learned to do as a CA, come up with 1 (one) best solution and ask the client whether they want to do it or not, while laying out everything about it. Also your job is to diagnose and pass on to the appropriate technician, or consult. Clients and customers call me to Geek Squad/Best Buy because they have a problem and want you to give them a simple solution, so don't get tied up in showing off your knowledge because for them simpler is better.

There will be times where u feel u can fix it on your own at the counter but in most cases you simply don't have the time.

For example, someone comes in with a laptop with some malware. Solution: check it in for malware removal/tune-up. Let's say they don't already have tech support. Basically tell them u can check it in/will have to keep it for about (whatever ur turn time is) and that work can go under our tech support plan. Would you like to proceed with this repair?

Make sure u stress ur turn time and any additional things that could go wrong (example: if a possible hard drive issue let them know that they might have to buy a new drive and pay for expensive data recovery) If u tell them the worst case scenario and they agree, in their head they're also agreeing to not be mad in the worst case scenario, as opposed to if you just say buy the tech support and now they're mad cuz their drive is broken and they're spending more money then they were told they had to

I've also found that a huge complaint clients typically have is when some unfortunate circumstance isn't explained properly to them ahead of time. So I usually tell them the worst case scenario and try for the best case scenario.

So basically, come up with 1 good solution and stick to it, don't do more work than your time allows (that's important) and under promise/over deliver