What effects price changes....

[Lexters]

Hi all,
After a very emotional day i was wondering what affects the ups and down of crypto coins? i tried to look into it and i cant seem to find what makes impacts.
It makes it difficult to guage when is a good time to buy and sell.
Is there any sites where i can input times and see what could have affected the coins. Im pretty sure it would just be speculation anyway but a list of ideas would also be great.

Thanks in advance for your time
Lex