Here are a number of sites that can help you during operation.  They perform a variety of functions.  You may want to look at all of them just to see what they do.

Logbook of the World (LoTW)

eQSL

QRZ.com

FCC ULS Search

Display Reception Reports

Time Is

Gray Line Map

Ham Radio Maidenhead Grid

Amateur Radio Maidenhead Grid Square Locator Map

Smoothed Sunspot Numbers

HF Propogation Tools

Google Maps APRS

APRS Direct

Repeaterbook (Maryland)

Ham Calculator