твой (tvoy) - refers to you (singular) ваш (vash) - refers to you (plural) but also to a stranger you have just met (formal singular 'you')
Hope it helps.
ч is almost identical English "ch" (like in the word chips or chirp), ть is softened t, almost like in Italian words ending with -tti, and closer to ц. Try saying t and ch and notice where your tongue is: when you say t the tip of your tongue should be touching the base of you upper front teeth, while for ch it is touching the roof of your mouth further back. For ть you keep your tongue to the front like for t, but you press most of it against the palate, not just the tip. I hope this makes sense.