If you cast on a stitch in the middle of a row, you'll have a hole because that stitch won't be attached to anything.
Kfb doesn't leave much of a hole, but does leave a little bar across the second stitch.
M1's, especially on thin yarn are a pain. For a purl M1, I lift the yarn from back to front and purl into the little loop in front. I find that if I can't get it in, I will put my needle into the back and then bring the needle up over the left needle under the yarn if that makes any sense.
"Trust the pattern!"
Time flies like an arrow, but fruit flies like a banana.
Hop aboard while we follow the cloud-covered van of knitting harmony, man!! Woooo!! --Hedgehog
IngridKH on Ravelry