For whatever variety of watch you purchase, most of us require some adjusting. If your watch band doesn't allow you a perfect fit, you will need to learn how to properly fit it to your wrist. Removing links, adding extra holes or shortening can be simple with the right tools or the right professional help.
Visit your watch retailer and request a fitting. Before trying to shorten your watch at home, you should consider that most jewelers will size your watch professionally for little cost. If you return to the vendor who sold you your watch, the chances are that they will size it for you for free.
If you have the most common form of resizable watch band, a linked watch, you will be resizing by removing links from your watch. Before beginning, try on your watch and determine how many links will be needed to achieve a perfect fit. Using your pin pusher (paperclip or other similarly sized object), remove links by pressing on the small pins holding the links in place until the watch band separates and the pin is free. One at a time, remove links and be sure to place the pin and links in a safe place so as not to lose them during fitting.
Reattach your watch band by fitting the ends back together and using your pin pusher to re-insert the pin. Store your extra links and pins safely in case of future adjustments.
If your watch uses a strap with holes, flexible bands or a more complex pin system you should consult your retailer to arrange for a professional sizing. If you still wish to attempt sizing at home, see the link in Resources or another good instructional website to read detailed information on how these more uncommon watches are sized.