Since you already know how to finger the chords, and how to change smoothly, you can put that aside for a while.

Mute all of the strings with your fretting hand. You aren't going to play any notes or chords, just lightly rest your fretting hand across all of the strings so that they don't make much sound.

Now, stroke down across the strings with your pick. Don't chop at them like a farkin' novice - stroke them, rolling your wrist as the pick slides down across the strings. The lower edge of the pick nearest the tip of your thumb should be the only part to touch the strings. If the pick hits the strings flat, it sounds like something little kids used to do, putting bits of cardboard on their bicycles to flap in the spokes. You don't want that. Stroke the strings with the lower, outer, edge of the pick.

Now do the same thing on the upstroke, with the upper edge of the pick that is closer to your wrist. Again; stroke, don't chop. Upper edge of the pick, not the flat face of it.

OK?



When that feels right, put on some music and strum along. No notes, no chords - keep those strings muted. Just keep time with your pick hand. Don't try to get fancy right away. Just keep basic time with your pick hand, strumming on those muted strings.

Chuffa-chuffa-chuffa-chuffa....



When that's comfortable, you can emphasize some of the beats by strumming a little more firmly. No chopping - you always stroke the strings, just a bit more firmly on the beats you want to emphasize.



OK; you're on your way. Have fun with it. Spend a day pretending to be a drummer. You can go back to playing chords later.