Your First Finger Picking Exercise
Even though I have been playing fingerstyle acoustic for some time now, I still work this into my practice routine. I find it works the muscles in your picking hand tremendously which builds dexterity and independence among your picking fingers.
When I practice, I will start with a pattern like Fig1. and repeat it over and over at a very slow tempo to warm up my picking hand. Then after several minutes, I will speed things up a bit keeping the pattern the same and staying on one chord.

I notice when I practice this, even for a few minutes at a time, my picking hand accuracy improves. They key is to practice it consistently and strive to increase your speed.
A word about speed: I know you’ve heard it a thousand times, but start slow and build up speed over time. Playing a million miles an hour is worthless if the notes aren’t clear!
With the ‘speed’ disclaimer out of the way, I have to tell you once you do build up some speed, this exercise is a lot of fun to play!
What styles of blues will this help you improve?
The deeper I study blues, and especially Piedmont and country blues, the more I can tell the masters spent quite some time building their chops from little etudes like this. This is a basic, fundamental skill builder. A skill from which to build upon. It’s hard to tackle songs from greats like Taj Mahal, Blind Blake or Etta Baker without paying your dues with exercises like this one.
Hope you enjoy.
Keep pickin!