how can you tell a first edition hardback book and are they valued more than a non-first edition book?

how can you tell a first edition hardback book and are they valued more than a non-first edition book?
The ISBN ends with a zero. In some cases first editions are worth more.
If there is no ISBN check for the year of printing or records of previous editions.

I must disagree. I have a copy of "An Unacceptable Death" which states on the title page that it is a first edition. However, its ISBN does not end in a 0.