Do's and Don'ts of yellow letters

[Sharif Mensah]

Hey guys so I'm about to start my first mailing list soon, I'm doing it the old fashion way by handwriting them. I just was looking at templates and all the letters are in print, I just have a problem writing in lower case letters, My current job has pretty much converted me to writing in all capital letters. 

I write faster that way but I wanted to seek advice on what would be the do's and don'ts for yellow letters.