I posted about the most recent Mercury Retrograde back in March, and alas it is back for almost the entirity of this month (August 2nd - August 26th).
According to Astrology Zone, don't sign anything (contracts, leases), as you may miss some fine print and end up in a big mishap later on.
Apparently Mercury is the governing planet of transportation and communication (namely speech). Why? I don't know. I'm not saying to take this information as the gospel or anything, but I have found that when Mercury is in retrograde, things tend to go haywire at work and at home.
Geminis (May 21st - June 21st) and Virgos (August 23rd - September 23rd) are ruled by Mercury, so plan on being affected and take extra precautions if you fall under one of those signs. Again, not the gospel, but better to be safe than sorry!
Typical things that happen when Mercury is in retrograde? Communication is off -- perhaps why you're fighting over little things with your significant other. You'll miss an appointment or it'll be cancelled, delays will happen, etc. Anything delayed or prolonged is a benefit to you, however, so don't try to rush it.
Back up your computers and get that oil change or inspection ASAP. Any machinery will reveal weak links during this period.
According to Astrology Zone:
"Why would the Universe give us Mercury retrograde? Because to move forward it is sometimes necessary to backtrack and reconfigure our paths in life. It is important to reconsider, repair, reflect, and reconnect. Mercury forces us to slow down and fix what's broken, and in so doing, rethink things. It also gives us time to get to projects we have put on the back-burner."
Best of luck!