Hello @jmiller,
Working with other designers can be tough, but there are tools that can make it easier. Here are some the ones I use, and ones I'm excited to use:
Figma is an online app primarily for design collaboration. It's easy to use and many people can work on the same document at the same time.
[Image source: Figma https://www.figma.com/]
Pros:
Cons:
Slack is one of the most popular team messaging apps. You can even send files, embed code, and call people. Slack has a large library of third-party plugins.
[Image source: Quartz http://bit.ly/2dm1zXp]
Pros:
Cons: None
Sketch is not a collaborative tool but with some of the great plugins available, you can simplify team collaboration. I use Sketch often to collaborate with developers.

Plugins for collaborating on Sketch:
GIT Sketch Plugin: A GIT client plugin that improves the review process and archives design iterations
Sketch Measure: Generate style sheets for your work with font sizes, colours, spacing, sizes, etc. for teams to work with.