Practice the scales a little slower, with a focus on smooth, even pick movements. Try not to bounce up and down on each note – imagine the fluidity of your smooth strumming motion, with or without a pick, only smaller. Hold the pick only a little harder than you need to in order to keep it from falling in the soundhole, where it will join your missing socks before their final migration to the TARDIS.
I find that for acoustic playing, I like a generally “medium” pick (.73mm or so), but I can still do good strummage with my usual very heavy picks. Thin picks are anathema to consistent playing – I only use those for the thwak thwak rhythmic sound in a recording, like a baseball card in the spokes of a kid’s bike.