First off, try showing the cat its reflection in the mirror. This will allow the cat to see other cats, albeit itself and help remove some of the initial shock or apprehension that it would get from an actual meeting with another feline.
After a few weeks of this, days in some cases, put your cat in its travelling cage and take it to a neutral territory. Preferably a house or room where neither of the two cats have been before. Many people may not know this but cats are territorial animals, especially the males.
Put both cages in front of each other and let the two cats see themselves. This will require some time before the two cats calm down, hence the bottle of bubbly and a comfortable seating arrangement.
When the cats have calmed down turn the travel cages around and open them at the same time. Distract both cats with some snacks and a piece of string. Get them to focus on you rather than each other.
They should begin interacting in a friendly way sooner rather than later. However, if there are any signs of aggression, then let it play out for a few seconds. Make sure there is nothing going on that could result in injury but let the two duke it out to establish some kind of pecking order.
Within a few minutes after that the two cats should become well acquainted and maybe even friendly towards each other.