You could still have a blog answering common questions & linking back to the main pages,
You can find many keywords for these using various tools such as ahrefs, semrush & ad planner,
Also, you have to make sure the titles are optimized for the top keywords for each tool,
Another approach would be to add some content in the tools pages under the actual tool section,
Including a couple of sections including the top keywords for each tool,
When it comes to links, you'll need links just like any other website,
Everything including guest posts, pbns, crowd, web 2.0s should work as long as the quality is good