"I understand that gmail formatting is pretty limited. What are some best practices for formatting in gmail? Are there any other apps that we like to use?"
SHORT ANSWER: Click on the A icon to bring up the formatting toolbar. Also, I personally like to write important emails in Microsoft Word, Google Docs, or plain old simple text editor.
FORMATTING, FONTS, AND COLORS: Click the A icon to bring up the formatting toolbar. Your formatting options will stay visible while you compose your message. For a full list of formatting options and keyboard shortcuts, check out this link (https://support.google.com/mail/answer/8260?hl=en).
REMOVE FORMATTING: You're writing an email, you copy and paste some text from another page, and the text's formatting comes along for the ride. It can be super annoying. If you want to remove the mismatch formatting, your best bet is to (1) highlight your text in Gmail and (2) use the Strike Formatting button in Gmail. It's the button on the far right of the toolbar that looks like T×, and it does exactly what you'd expect: removes all the formatting from selected text and resets the styling to Gmail's default.
USE MICROSOFT WORD OR GOOGLE DOCS: This is just a personal preference but I really love to compose my emails separately in Microsoft Word, Google Docs, or plain old simple text editor, especially for important emails to the boss! Once I'm all happy with what I've written, I just copy & paste from my word processor to Gmail. Keep in mind Gmail's font selection is pretty limited so don't go too crazy!