I went to Mexico the watch automatically changed an hour back. I am now home in the USA and I can't get the watch back to an hour ahead Casio G-Shock 2688 gw-330a

Is the Year right? If you are using 12 hour display the watch maybe 12 hours ahead or 12 hour back.

You can get instructions from the Casio web site.

Go to the casio web site "casio.com".

Select "support" and the "manuals",
watches;

Accept terms

Select "watch manual archive"

Read the number of the back of your watch and enter it into the search box

It sounds like your watch is set to the wrong time zone. If you haven't got instructions, you can get them from their web site.

You can get instructions from the Casio web site.

Go to the casio web site "casio.com".

Select "support" and the "manuals",
watches;

Accept terms

Select "watch manual archive"

Read the number of the back of your watch and enter it into the search box

Hola se?or! Hay muchas lugares en que puedes comprar este reloj.
Puedes usar eBay, hay personas que venden relojes y ellos te envia.
Usa esta enlace: http://shop.ebay.com/i.html?_nkw=Casio+G-Shock&_sacat=0&_odkw=Casio+G-Shock+GW300CA-1V+Wrist+Watch&_osacat=0&_trksid=p3286.c0.m270.l1313

If you cannot find the automatic way of setting the hands, you can manually reset the analogue hands by pressing the mode button until you reach the "HS" mode and using the 2 or 4 o'clock buttons to adjust the hands.

go to support page on casio. and get your manual. youll probably gonna look for a 3 or 4 digit number located at the back of your watch. once you got the manual. go to page 4. and follow the steps of "Hand Home Position Correction". that should fix it.

i also have ga 110c and i have encountered this issue

You need to manually adjust or set the hands to the home position as they are not where the watch thinks they should be. This can happen when you bring your watch close to a strong magnetic field. Look in the manual to do this. Afterwards your watch should set to the correct time.

make sure its set to do automatically...or else it needs you to do it manually

I’m happy to help further over the phone at https://www.6ya.com/expert/jovani_c02b023fe087f6cd

Use this page to download a copy of CASIO watch manuals in PDF format. To download a PDF file, enter the four-digit (or three-digit) module number marked on the back cover of your watch.

http://world.casio.com/wat/download/en/manual/

You will need a pdf reader on your pc, you will find all instructions in there.

If you don't have a pdf reader you can get one from
http://www.foxitsoftware.com/pdf/rd_intro.php

How to set the solar power time change, my watch has remained with the same time; and not one hour ahead (spring forward) ?