1. concise and straight to the point
2. fact check
3. spell check

Serif is the industry standard ( Times New Roman, Bookman Old Style), but personally I prefer the aesthetic of sans serif (Arial, Futura, Century Gothic). Size 12 to 14, single spacing.

Don't send in wall of text if you can deliver the same message in a few lines. That's the main point: you want to deliver the message, clear and simple. Avoid showing off your vocab where it's not needed. Use industry appropriate terms.

Calibri is fine. Readability is more important than which exact font you are using. So avoid things like Comic Sans. Unless specifically instructed to write in certain format (in my case, Century Gothic size 16 1.5 spacing), you are free to use anything you want.

1. concise and straight to the point

Ideally the first page is the summary of everything. People can get important fact/points with a glance if they are in a hurry. Following pages are elaboration of points in first page.

2. fact check

3. spell check