Hey 'Stubs'!
First of all, good piece of content and good site.
Second of all, the Moz Keyword Tool is not perfect. It only will check general rules with the EXACT (ie. high is different than highest) keyword you put in. Try using the keywords 'high paying jobs', or 'highest paying jobs' when using the tool for this page.
It looks as if your entire site has dropped in rankings. You were ranking for 184 keywords in Aug 2014, and you are now ranking for 104 (SEMrush data - Australia). A major drop like that is likely due to an algorithm update or refresh (Panda 4.1), or a manual action (this is unlikely because rankings would have dropped further).
I see that this page is important to you, as it currently ranks for 59 of the 104 keywords your entire site ranks for (SEMrush data again). There is a chance to do some basic on-page optimization on it.
- Title Tag - good
- Meta description - good, but could include variation of keywords (high vs highest). Make sure to keep it enticing though.
- Alt tags - None of the images in the post itself have alt tags....add alt tags with keywords where appropriate.
- H-tags - I see that the site is using h2's for a lot of the formatting of menu, navigation and sidebar content which is not best practice and may not be helping. The title is set as the h1, and the jobs as h2's, which is good.
- Content - the content is good! However, you could include more variations of the target keywords on the page. Not to the point if effects the way it is read of course, but there is room for adding additional variations of the page.
Overall the content is good, but the pages outranking you also have good content > https://www.google.com.au/?gws_rd=ssl#q=high+paying+jobs+in+australia. The fact that it IS good content is the only reason it is still on the home page for that search. If you look at basic metrics like page authority and domain authority everyone on that first page has higher authority than you (DA: 13, PA: 24). I can see that your site is only about 2 years old (at least the domain is), so that's clearly a contributing factor and gives you a disadvantage.
I would recommend doing some basic on-page optimization, and try to get some increased traffic by sharing it on social media.
As for the rest of the site, keep creating great content and your authority will slowly climb.
Hope that helps!
- Marcus