How do I copyright a photo- I have some awesome pics and I would like to make a calendar. any help? Thanks!!!!

I have pics from lightning to lizards to a giant sunflower and other blooms in my garden- any clue as to how to copyright them? Hoping not to spend TOOOOO much cash- need to save that for gas....... C"MON November- we need somehing different! Took them with my Casio EXILM. also can I copyright photos (I took) of other people without their permission?