How this Grace thing works...?

Ok, so my last post or two have been related to religion and beliefs but that is what has been on my mind.

How does one believe?
How does one know what to believe?
How does one keep believing?
How does one know what to believe?

I have alot of respect for someone who has faith and/or a religion. To be able to believe that there is someone who watches over us and takes care of us must be an amazing feeling.
A feeling that I wish I knew, but my head always leans to the "yes, but what about..."

Ending with two questions today...
Do you believe?
What do you believe?