Blurry, out of focus snowflakes

Hello everyone, I've got two queries regarding After Effects. I'm currently trying to do a Christmas animation with snowfall. Now, I don't know After Effects, and I just basically dove into it, so the answer might be really simple and I've just not been able to figure it out. I've actually seem to have accomplished the sort of animation I was after, but I'm struggling a bit with my snowflakes and I'm hoping that someone with a bit more After Effects expertise could offer me some advice. I've made snowflakes in illustrator, which I have imported into After Effects, but in the rendered version of the animation the snowflakes turn out blurry and not at all clean "cut" as they are in Illustrator. I can't for the life of me, figure out why this is. I have a text animation in the animation as well, which looks sharp and with the text the shabbiness of the snowflakes just really stand out. I saw a tutorial where you were to separate the illustrator layers and import the object as a composition, which I did, but it doesn't really seem to do much for the snowflakes, they are still blurry. I'm not sure if it is because the original composition is too small, and if that would be the case, can enlarge everything or is it a case of starting over (and if so, what would the recommended composition size be?).

Another issue is that I've used the "twirl" animation to create the snowfall effect, which in many ways has achieved the desired effect. But there are a few oddities, such as that some snowflakes seem to appear quite sudden, in the middle of the screen, or then twitch from one side to side. I guess the twitch is part of the effect, but I've slowed the movement down significantly and these sudden twitches on the screen are kind of distracting. Is there any way to avoid such twitches, and any way to manipulate the effect to have the snowflakes simply flow from top to bottom?

All and any help is appreciated! A for-dummies response would be appreciated, since I don't know the technical ins and outs of the program.

Thanks!

/Mala