When I started learning Chinese, I learnt like this:
Ci" sounds like the ts in cats.
Zi pretty similar to Zi in Zion.
Si like the "cer" in certain
Shi like in "shirt"
R for me is most difficult, it's like the first r in tractor.
J like the j in jump.
Q like ch in cheese.
X like sh, (Xi like she).
If you can hear the sounds it's easier to hear the difference, but I hope this helps a little in the meantime...