There's nothing wrong with hitting skip on anything you're unsure of or if don't want to deal with it at the time but of course if everyone did that it would hang around forever. A change was made to the wording of one of the buttons from "Looks Good" to "Looks OK" with the idea being that it felt wrong hitting "Looks Good" on an answer that was incorrect or a bit on the brief side.
If you do want to deal with the the non-obvious ones you've mentioned my interpretation of some general Stack Exchange guidelines combined with a few things I do are:
If the answer tries to address the question but is wrong (in your opinion) you can comment and/or downvote it. Because it's not delete-worthy just for being incorrect you can press the "Looks OK" button at that point.
At your discretion if you thought it was dangerously wrong you could also hit skip to give it a bit more attention from others and then go back to the answer and comment / downvote.
Same applies for anything a bit brief / confusing as long as it's an attempt to answer the question and may be at least somewhat useful. The VLQ queue is mainly about deleting posts beyond saving that really have no value.
If the problems are mainly grammar / formatting related and you can edit into shape then do so and then it should "Look OK".
Regardless of what you do if it looks like a genuine attempt at answering the question comments are good with anything that can be improved. It's best for everyone if the author takes any advice on board and makes the answer as good as possible.
Remember you can leave a comment and recommend deletion with no comment necessary if you think the answer should be deleted but none of the reasons on the list fit. An example might be if the poster has badly misread the question so it really doesn't answer it even though their intentions may have been good.
Another thing to remember are the various ways an answer can end up on the low-quality review queue, sometimes it won't be for a valid reason:
A user with a reputation of 15 or above can flag it. Part of the reason says "This answer is unlikely to be salvageable through editing, and might need to be removed" but I've seen it used incorrectly and did the same myself several times early on for answers that were just wrong in my opinion.
The system will automatically place short answers in the queue. Some questions will have a brief to the point answer and things like code and schematics don't count towards the word count. An answer like "This circuit will solve it" followed by an awesome and innovative schematic will probably end up on the queue.
While Stack Exchange don't say how their spam prevention works (for obvious reasons) I believe that may also play a part in what goes into the VLQ queue. I saw an answer in there recently that had the "identified as possible spam" banner even though it was a very good answer. Might have just been someone unlucky to have an IP address recently used by a mass spammer.
In general just use your best judgement of whether an answer has any value. An actual deletion takes six < 20k users, three 20k users or a moderator and reviews are dismissed more easily than the close vote queue so a lot more consensus is required. Much like close votes on some edge cases you'll see some level of disagreement between users and even between moderators on whether some answers should be deleted.
