The real thing to remember that many do not is linking patterns in relation to the theme.
For example - going after EDU websites is great. But reverse mining, and asking for links from websites that those EDU links to is also extremely effective, and often the conversion on those requests is higher. Some EDU's have strict policies in place where even if they loved the content, they are not always able to link.
One thing that works great Wheel if you have time is to create a link matrix, similar to what many of the larger subscription based programs have done.
I take the total links from authority websites pre 2000, and create a DB of all of the websites they link to.
I then cross reference this with the backlink mine from all ranking websites for the top 5 keywords in the genre and websites ranking in the top 20 positions.
By far and large, the union of those links are your gems, and focusing on those will not only help you satisfy authority, but will ultimately also give you practice and down to earth links that Google loves and has ranked others well with.