Oh, I feel your pain! My toes are the same way.
Unfortunately, when I first started riding, I was always told, "heels down." So I practiced and practiced that, until I got it. But I was never told "toes in." Its VERY easy to have your heels pushed way down, and your toes sticking out the sides. Hehe.
I found what helped me, was just setting aside some riding time to just focus on my toes. Try it at a walk first, and put your toes where they need to be. Don't really focus on other things, just your toes. I did this on a trail ride, where I didn't really have much to do otherwise, and I told the lady riding behind me to tell me each time my toes pointed out. It was annoying, but it helped.
Also, another thing someone told me, was ... look at the way you walk normally. Do your toes point straight, or do your feet kind of point out. This can have a large effect on how you ride. But for me, my toes point straight when I walk, but turn out when I ride.
Lol. Sooo... maybe that theory doesn't work for everyone.
But yeah, I would suggest just really focussing on your toes for a couple riding sessions. Take a break when you need to, take your feet out of the stirrups and roll your feet around. But keep at it, and eventually it will improve. I found mine have gotten better.