I've been doing the service desk for a while now, and I feel confident in my abilities. Obviously NASATS and all, but there are some general things that I think are universal.
Something my supervisors like about me is that save for serious circumstances (fraud of any kind/completely bizarre situations/backup) I rarely call them over for assistance. This is because the store really does give us empowerment to solve most general problems. Please remember that you are absolutely allowed to adjust prices, make exceptions, and hand out apology coupons (all within means of course) in order to appease guests. You want to make sure they leave happy, but that doesn't mean that you have to give them the entire store. A couple dollars here and there, a false "Look, I'll make an exception for you *THIS* time", and that's usually all it takes for me.
Of course, it's not always that easy. Oftentimes people will yell and demand a manager, and once that happens the situation is out of your control. The fact is, some people just want to cause trouble. People have crappy days and want to be dicks. It's not your fault.
(Of course, if something IS your fault, own up to it and find ways to rectify the situation. But 49/50 times the angriest guests will just be angry for the sake of being angry).
So that's my advice on the customer service side of things. Use your empowerment to your advantage without giving away your store. Realize that a lot of guest services is just making quick decisions. If an item is mismarked as $9.99 and the guest was charged $11.99, and it's one item, do it.
If it's $100, or anything else like that, call over your GSTL/GSA/LOD. But for most situations, trust your judgement.
Be careful with price match. This is a big one. Team members cannot use their discount on any price-matched item (exception - Target.com). This is a big deal at my store and team members have gotten in serious trouble over it. Do not price match out-of-stock-online items. Do not price match other Target stores. Do not price match your local retail store without a valid print ad. And so on.
As for label auditing, just...please watch out for those white labels. When doing returns, pay close attention to POS. The system will automatically print tickets. Do not lose track of this.
For example, if you scan a shirt that your Target no longer has on file, a white MISSED SALVAGE ticket will print. Attach this ticket to the item immediately, throw it into your labeled Salvage box or bin, and assist the next guest. For some returns with 5 or 6 MISSED SALVAGE tickets (usually large clothes returns), put all the tickets with all the clothes safely off to a side corner, assist your remaining guests, then immediately continue placing each ticket onto its appropriate item and into the Salvage box or bin.
If you tell the POS that "something's wrong - defective" (K1 - K1 immediately after scanning the first item for return), all items will be labeled DEFECTIVE SALVAGE. Deal with them how you would deal with MISSED SALVAGE items - ticket onto item, item into bin. Make sure only items that are not in resellable condition are defected out.
Some items will print out CRC tickets. These are electronic items that require being recycled safely, and at my store are more important than Salvage (iPads are typically more expensive than clothes, I suppose). Deal with them how you would deal with Salvage merchandise, but make sure it gets put into its appropriate CRC bin.
Toss is anything that shouldn't be defected - food, broken glass, baby bottles/strollers/etc. Toss is destroyed at Target rather than shipped off to a third-party vendor or recycled (like Salvage/CRC). At my store toss is a bit less important, just make sure each item gets its white TOSS ticket and then gets thrown into the toss bin.
Lastly, some items print weird tickets. They're all super weird, like one is a box with the letters FL printed inside. One is a picture of a battery, stuff like that. Pay close attention to these. Before the ticket prints the POS will display a screen that writes ESIM BAG AND SEAL. You should always see this screen. These items are bagged in a plastic bag, sealed with a ziptie, and the label is taped to the OUTSIDE of the bag. Make sure these get placed in the appropriate ESIM bin.
QMOS. QMOS is any milk/dairy/fresh/frozen food that cannot be defected out. No need to enter these into the system - bag and seal them, then place them into the appropriate QMOS bin.
Please keep track of these labels. Guests always ALWAYS come first at the service desk, but if you only have one or two defective items and one or two defective labels, at my store we quickly deal with this process in between each guest. Be quick about it - it should take no more than a few seconds max. Just know that at the end of the day, all of these items will be put through inventory. YOU will be accountable for any missing items. I know people who have been put on coachings/CCA's because of egregious errors, although I have misplaced salvaged clothes a few times and have heard nothing about it from anybody.
There is so much more to it, but you'll get better with actual hands-on experience. For starters, those are the two biggest things to have eyes on - solving problems logically and fairly (you are usually either the first or last person the guest will deal with at Target, make their shopping trip a good one), and auditing items. It's not hard at all despite how long this post is, just learn each individual label, and you're golden.