There are three levels of worship that I feel important for you to know and be able to explain to those who question you about praying to Mary and to the Saints.  

The three levels of worship are:

Latria

Hyperdula

Dula

Latria means worship and worship is reserved only for God.

Thus, remember the Ten Commandments and how you shall have no other gods.

Hyperdula means honor and this we do to Mary.  We honor her since she is the Mother of God and Jesus while on the cross dying for our sins gave her to us as our mother.  We DO NOT pray to Mary.  Asking Mary to pray for us is no different that me asking you to pray for me.  Well, she does have direct intercession which is more than we have.

Dula means reverence.  We show the saints reverence.  We should do this because with them we are part of the Communion of Saints.  They are part of God's Glory now and we can turn to them for intercession as well.  We Do NOT pray to the saints; again, it is no different than me asking you to pray for me.  Well, they have a pretty closer link to God than we do.

I hope this explains clearly the levels of worship.