Suegorgeous, find yourself a piano somewhere, find middle C, now the next note up is D. Play the white notes only from D to d and you have just played a Dorian scale! If you can get that sound into your memory banks, then work your tune around it, that should sound 'folky'! And if you want Mixolydian, find the G, play a scale on the white notes only and there you are. And if you do the same from A, you're playing/singing in the Aolian mode.
An 8 note scale from any white note on the piano has a modal name, tho' some sound very strange and very few people ever use them.
It's not the 'experts' way but I find it a very easy way of hearing what the modes should sound like, then I just move that sound to any singable starting note. Then you don't have to talk about C Dorian or D Mixolydian or any other fancy words, you just hear it in your head and start singing it from where you are comfortable.
Robyn