On the topic of pick technique maybe you could give me insight on how I could go about finger picking?

I have no problem putting my fingers together to create a pick with my nails. I do, however, have an issue with making singular strings sound clear.

i.e. If I'm playing a G chord and I want to emphasize the G base note on the 6th string with my thumb, it will end up ringing out fuzzy and incorrectly. The rest of the strings will be fine because my finger nails will graze the strings.

Do I need to hook my (nonexistent) thumb nail on the string to make it sound clearer or is it my unrefined technique? I apperciate any and all help :)