I used the "Deaconess" pattern found here, but after making a couple masks, I tweaked the pattern so that the mask would fit better over the nose, and I found a process that worked for me. A face mask with straps that can be tied will provide an even better fit, so that will be the next change I make moving forward, but in the meantime, I hope this picture tutorial will be helpful. Feel free to modify and adapt the pattern, just as I did.
Tie straps are completely adjustable, so I will make face masks with ties going forward. Plus I'm out of elastic, as is Walmart and Jo-ann's. And I have lots of cotton fabric...

John 16:33
"For everyone who has been born of God overcomes the world. And this is the victory that has overcome the world - our faith. Who is it that overcomes the world except the one who believes that Jesus is the Son of God?" 1 John 5:4-5 "Whoever has the Son has life; whoever does not have the Son of God does not have life." 1 John 5:12
As I sew more fabric facial masks in the days to come, my prayer is that those who wear them will not just overcome the coronavirus, but overcome the world by faith in the Son who gives eternal life to those who believe.
~ Debbie