The folks at the watch and jewellery stores may make it look easy to take out watch links, but that may be because they've had lots of practice. It's true that this task gets easier with experience, but what makes it so difficult for beginners is that it requires precise tools as well as a fair amount of brute force. You must be able to apply about 9.07kg. of pressure using a tool with a tip smaller than the head of a pin to remove links from TAG Heuer watches. If that doesn't sound like a problem to you, go ahead and give it a try.
Wear the watch and pinch the excess length together to figure out how many links you need to remove. If you need to remove one link, you can take it from anywhere on the watch. If you need to remove an even number of links, you should remove an equal number from each side of the watch face. If you're removing an odd number of links, you should still take them from both sides of the watch band, but it's up to you which side you want to take the extra link from.
Look at both sides of the watch band closely. On TAG Heuer watches, the links are connected by little metal bars, and one end of each metal bar is larger than the other end. When removing the bars, you'll need to push on the little end. When reinstalling them, you'll need to push on the big end.
Figure out exactly which links you'll be removing so that you don't get confused once you start taking everything apart. Designate an area where you can pile all of the removed links and pins.
Remove your desired links by pushing out the pins holding them in place. To do this, hold the band in one hand while holding the Bergeron pin tool in the other. Use the pin end of the tool to push on the small heads of the pins. You will need to push with a great deal of pressure at first, but once each pin moves a little bit, it will be easier to remove completely. This is because the pins in the links of TAG Heuer watches are notched on the large end, and these notches hold the pin in place. Once you push the notched part of the pin through the link, it will move more easily.
Reconnect the links that need to be connected. To do this, hold the two unconnected links together and push one of the pins in. Remember that TAG Heuer watches have asymmetrical link pins, so you will need to insert the small head of the pin into the side where the large heads are and push it all the way through. It won't go all the way in by hand, so you'll need to finish pushing it in with the Bergeron pin tool. When the pin is in place, you may hear or feel it lock into its fitting. It should be flush against the side of the watch band.
Watch stores can do this for you quickly and cheaply, and virtually all watch stores will be able to service TAG Heuer watches even if they're not specifically associated with TAG Heuer. Unless you think you'll be removing lots of watch links in the future, this is probably the best option, because the Bergeron tool usually costs about as much as the service to have this done for you.