Challenging any highlander to a drinking competition is probably a sign that you have some kind of a death wish. People in the highlands take such things rather seriously, and even if they get to a point where they are barely able to stand they would still not be willing to give in without a shadow of a doubt. You might feel like you have a high tolerance for alcohol, but in spite of the fact that this is the case there is no doubt that a highlander would be able to drink you under the table.
Still, the thought of participating in a drinking game is quite enjoyable so you might be willing to give it a shot. If this is the case you might want to consider visiting https://issuu.com/highlandcommercegroup/docs/top_bars_in_highland.docx to find all of the best bars in the area. Once you find a bar that you are interested in, the next step would be to go in there and find a highlander that you are brave enough to challenge. Try looking for someone that has already had a few to drink. Not only would they be easier to defeat due to the copious amounts of alcohol they have already consumed, they would also never refuse the game since they are at a point where they are incapable of refusing anything.
You need to start the game slowly and let the other person drink themselves out. The key is to drink more than the other player, not to drink faster than them. If you drink too quickly you might make yourself lose the game, so take big but reasonable sips that can help you to keep up with your partner and keep their lead minimal.