Helium has given leapfrogging option for you with several intentions. The foremost is to improve the quality of the content of your article; the second is to set right minor mistakes and slips that you would have done in your otherwise good article and thirdly, by doing the above, to improve your article's rank.
Since, as a writer in Helium, your writing star status is the one that determines your upfront earning potential, the best tip for leapfrogging an article is always to concentrate on such of your articles that have fallen below 50th percentile.
One basic reality about Helium's rating system is that it concentrates more on top ranked articles (i.e. articles above 50th percentile) to sort them out in the correct order and the rating engine's concern about lower ranked article is rather less. It means, more number of ratings take place in the upper half. As more and more articles get into the title, they get inserted at the mid point. Articles below the mid point tend to get pushed further down in the process; where the articles are too many in number, the below-the-mid-level articles get trampled upon and get lost.
So, even if your article has much better content and quality than another article much above in ranks, the possibilities of it getting lost in the crowd is quite a reality in titles where there are, say 10 and more number of articles. If you are quite sure that your content is already good enough, do not hesitate to leapfrog the article, with very minor tweaks and improvements. If leapfrog gets accepted, then you will find your articles rising rapidly towards top (if the content is really good).
The next tip is to leapfrog your article even if there are minor typos. Though the preferred and recommended method is to get it fixed by writing to content@helium.com, there is a strong reason behind this advice. Why?
When you go through your article after a long time, you will not only notice typos, but also some petty slips in grammar, some sentences not very neatly written, some lines which seem to duplicate the content in a previous paragraph in a different way, some too-long-paragraphs that are worth splitting and so on.
Why not do all these minor tinkering work while you are setting right the typos? It's like drinking a glass of orange juice when a glass of water is good enough to quench your thirst! Why not, if it is contributing to your health?