Let's face it, the majority of Blue Tongue Skinks in the pet trade are currently imported Indonesian (or subspecies) Blue Tongue Skinks. This could mean that the unsuspecting buyer who is expecting the easy handled captive bred blue tongue skink, ends up with a hissy, reclusive, and defensive animal that they are not prepared for.
By socialize, you can "socialize" this bluey to the point that handling does not put as much stress on the animal. I really mean get the skink used to human contact so that when handling is needed (or desired by the human keeper) it does not put stress on the skink. Stress causes a lot of issues in captive reptiles. Ranging from disease, to going off feed, just putting them in a really bad mood. So really, when working with the Wild Caught reptiles, taking steps similar to this can help them adjust to life in captivity.
The first thing to remember is always stay calm. It can be quite the task of working with an animal who is deathly afraid of you and only wants to run away. It can also be intimidating to have a blue tongue skink gape it's mouth, threatening to bite you, and hiss. You might get bitten, and you have to accept that. Take it from me, when it comes to Blue Tongue Skinks, the thought of being bitten is a lot more painful than the bite itself. Anyways, 99% of the time they're just bluffing, and as soon as you go near them they stop bluffing and try to run away.
Okay, so now you've overcome your fears of the not so terrible Bluey bite … Well what's next? Patience. This is not going to be an easy task. This bluey was trapped (or farmed), and shipped to a pet store. It probably does not trust people. So its going to be a slow and steady process.
This is where I would start. Sleep in a tee shirt for a few days (make sure you are not wearing any perfume or deodorant before, have a shower if you have some on) and then knot up the openings so the skink can not get into it. Place this in his enclosure and leave it in there. He'll hide under the shirt and lay on top of it and start linking up your smell with security and safety.
I'd move on hand feeding. The title of that is pretty self explanatory, off the skink small bits of food by hand. If the animal is too afraid to try, do not force it. Just let him / her eat by yourself and try again next feeding time, they will catch on eventually.
Once the Bluey will let you pick her / him up with only a little bit of hissing, and no Gaping, start handling sessions. Just let the skink walk on you and explore. Start for the first week, keeping these very short, about five minutes. Week two bump it up to ten minutes. Week three bump it up to fifteen. Once the skink is comfortable in the fifteen minute range of handling you should be good to go for longer. However, remember the skink still needs the heat and UVB lighting in it's enclosure so do not keep them out for too long.
Remember, you will have good days and bad days. One day you might think you've made real progress and then the bluey might be right back to square one. They will come around, you just need to take the time to do it!