As far as shipping and packaging go, I know that I honestly put a lot less time and effort into them than I should. Personally, whenever I order something and it comes in a cute box or nice package with tissue paper, or has a cute little note, I am always very excited to open it. Even if the item is not quite what I expected, I will almost always give a five star rating just for the packaging and will usually leave a note too, so that it shows up as a 5-star rating on the buyers profile. Of course, the only exception to this would be if the item is not what I ordered or was described incorrectly and came dirty or stained. When I package my sales, I usually do not use tissue paper, but I do throw in a thank you note to each package, and I always add a cute little sticker on the shipping label. For anything that is priority mail, I just use priority mail packaging, which you can order for free here, and for anything that is first-class mail, I usually use poly mailers from Amazon.

One of my favorite YouTubers, McKenzie, always does really fun “ship with me” videos. Feel free to check out her latest one here. I would definitely recommend taking tips from her on how to package items. She packages her items so nicely, which certainly makes a good impression on the buyers. She has mentioned in multiple videos that she often has repeat buyers, which could certainly have something to do with the extra nice packaging that she uses. Packaging can make such a big impression on a customer, and it can be very helpful in increasing customer satisfaction. It makes it seem like they are receiving a gift, even though they are the ones that paid for and purchased the item.
As far as actually shipping out an order, I would recommend doing it as fast as possible. Not only will this increase your shipping time statistics, but it will mean the buyer will get their item sooner. The sooner the buyer gets their item, the sooner you will get paid. Personally, I used to drop off my packages at the UPS store everyday or every other day, since it is close to where I work. However, I dropped some packages off there once, about a month ago, and they did not start tracking for almost three days. Ever since then, I just drop them off at the local post office instead, which is a little more out of the way, but is definitely worth the extra drive since they usually take no more than 24 hours to start tracking there. Also, if I drop off a package at the post office, I will typically just use the little drop box so that I do not have to wait in line, and the drop box also makes it so that I can go any time of the day or night.
You do have to be careful on Poshmark because they have a few specific rules about shipping out items. On Poshmark, if you do not ship an order within seven days of purchase, the buyer can cancel the order. In addition, the app allows a buyer to cancel their order within three hours after purchasing it. (This does not apply to the order if they accept an offer from you, or if you accept one from them, but only applies to outright sales.) I would suggest waiting at least the three hours to drop off their package, even if you have it ready before that time, and even if it means that you have to wait an extra day to ship the item, just so that you will not have to deal with the hassle that would ensue if you dropped off a package and then the buyer canceled the order. What do you use when you package orders? Let me know in the comments below!