Cotton yarn is much less stretchy than wool or even acrylics. Try to repeat the cast on that was loose (before things tightened up) or try exaggerating the looseness of the cast on and knit sts. Just drape the yarn over the needle so that you have no tension at all. Don’t pull anything. See if that will get you started and you can learn to adjust the tension of the sts later.
Casting on newbie here
I’ve tried the backward loop cast on and the knit cast on. I had issues getting the needle in the backward loop so quickly gave up on that one. The knit on was difficult and I don’t think I was doing it right (I was watching the videos here on this site). I’ll continue working on the long tail cast on. Making it loose.
I’m going to sign up for a class at one of my local yarn shops, we have Michaels and a small yarn shop on the opposite side of town. I think I’ll take the class at the small yarn shop since it includes 8 classes for $50 I think and at Michaels it’s one 2 hour class. Not much I can learn in 2 hours… I already took that class years ago and wasn’t impressed. There was very little instructor/student attention at least for most of us.
So I’ll keep trying until I can get to a class.
Wow. I just switched to English style knitting and my stitches are loose now. Quite loose. I’ve only gone a few small rows but I’ll frog it and re try with a tighter cast on and see if the stitches are appropriately tighter. Woohoo! I think I’ve found the answer! 
I made an appointment with someone through betterfly .com which is a site where you can find a personal instructor for many hobbies, activities, etc. The cost is minimal to me, much cheaper than a class at Michaels, and I get one-on-one time with someone to help me. So we’ll see how I can improve. yay!
Well, try going down a needle size, if you have one. And I’m glad to hear you found a tutor, that should help you a lot.
I don’t mean to hijack your thread but I have a cast on question and didn’t want to make a new thread for that, I hope you don’t mind.
I don’t do the long tail cast on method, I use 2 needles to cast on. Now I want to know if I should be leaving a long “tail” with this method? Also when I put my very first loop on, I tie a knot then continue to cast on from there, is this really wrong to do? So far with my scarf and two hats I have made I haven’t had a problem with it coming apart.
Are you knitting on? w.knittinghelp.com/video/play/knitting-on-continental It starts with a slip knot, though there may be another way, I don’t know. As for a long tail, you need to leave enough to weave in (generally suggested @ about 6") or in some cases you might want to leave enough for a seam. The “long tail” method uses the long tail in the cast on.
I do it like this. http://www.youtube.com/watch?v=5T43J_cYlSU except she does a slip knot and I do not, I just tie a knot. I don’t leave a long end because I dont want to have to weave it all the way through at the end.
You should leave at least 3 or 4" or longer, depending on how you plan to weave in the tail. Most people use a blunt darning needle, and need about 6"; I use a crochet hook and can get by with a couple inches. And yes, the CO shown in the video is the knit or knitted cast on. It’s better to use a slip knot but if you just want to tie it on, CO 1 extra and when you get to the end of the first row, don’t knit into the tied on stitch, just drop it off. With a slip knot you can tighten up the end st a little, but you can’t with the tied on loop.
ah interesting about dropping it off if I’ve tied it. Does this mean I can leave a short tail?
Leave as long a tail as you need to weave it in later. Better leave 4-6" on your first time so you know you’ll have enough.