I was just wondering how people make clothes for their characters in stop-motions?

just cloth sewed to make the clothes or plasticine

how do you sew tiny clothes?

Very Carefully
I tend to make any body parts that I don't need to move out of hardening clay, either coloured or neatly painted. That way you get the nice plastacine effect but it doesn't get all mangled. If I want a jumper, or something with sleeves I try and make the sleeves a different colour, that way there is still the illusion.
Hope this helps!

yeah you could do that and also when you make long sleeves which are easier and look better remember a cuff...it looks good and more realistic.

what type of hardening clay would be good for making clothes?

eerm i just use das which isn't that good so i wouldn't advise it...sorry i don't know

sure, but how do you make shoes?

well it is best to use plasticine as it will move better with the armature especilly if you are using a ball socket armature, as they have jointed feet

I personally use Newclay, by the same people who do Newplast. I do not recconmend using it if you want any kind of movement though.