2 things about carrying your yarn up:
you have to be careful of tension: you want the string on the side to be "JUST RIGHT" for the length of the knitted section. You do not want that strand to pull your knitting too tight and you do not want extrem amounts of slack in there, either (but that would be the lesser problem)
When carrying the yarn up, you do not really want those long floats. You want them wrapped up.
so: every time you come to the edge of the lose ends, wrap your working color around the strands that get carried up and therefore keep them "cought" up in your edge. That makes it a lot nicer looking and easier to seam in the end. Also you have less tension problems, in my eyes.
When you drop one color and start the next, make sure, that your new working yarn is coming from underneat the old one, so that the old yarn gets cought right away
The wrapping in on the side is less important than the tension. You just don't want your sweater to pull up on the sides.
The state of your work in the picture: the white yarn is pulled too tight, in my eyes. But since there are no white stitches, yet (in the pic) you can just stretch your work down on that edge to make more white yarn pull in and then you have it there with tension. It just takes knowing that the issue exists. I don't want you to have to learn the hard way when you are done.