Okay, how do you play single notes? It's a little self-evident that you strike the strings with your picks and you make notes, but you want to strike them cleanly. The thumb goes forward, the fingers come toward you. You don't strum. Pedal steel is not a strumming situation the way a guitar is. It's a very declarative instrument. You have to know in advance what you're going to play and when, and you probably shouldn't be playing the whole time anyway. You need to strike the strings cleanly.
Now, the beauty of the pedal steel is that you don't have to strike every single note, because that's what the pedals are for. Pretty much every other note or so, you played, you struck once and you got three notes. That's pretty good. The same applies for sliding. I don't know how many notes we got there with only one strike, but you're starting to get the idea. That's what lends to the fluidity and the originality of this instrument. The pedals are there to do some of the work for you and will fill in some notes. It gives you the time to get to the next position. That's how you have this wonderful...
Sp you're doing combinations of strings, you're doing single note stuff. Basically, you're going to want to find some exercises that encourage you to follow certain rolls and stuff, sort of banjo roll type things, or you're doing series of rolling motions that's sort of like a bluegrassy kind of feel. You're going to be using your tone bar to slide around and make extra notes as well. So a combination of picking, using the pedals, and sliding is how you're going to get your single note and any other kind of note happening with this instrument.
You need to block a little bit, as I mentioned before. You don't want everything to bleed into everything else. I use a pick blocking where the pick comes back down to rest on the string after you've struck it. So it rings, but not any longer than it has to. If you're playing fast, especially, it's a desirable way to keep the notes distinct and neat and try to make it sound really polished and smooth. That's basically how you would start picking single notes on a pedal steel guitar.