Hi, i work at a shelter and we introduce dogs to each other every day, i will explain how we do it at work, which works really well.
Meet in a park or somewhere quiet and unfamiliar. Have both dogs on leads. stand about 10 -20 metres away form each other, and slowly start walking in a large circle clockwise, and have the other dog going anticlockwise. Keep walking in circles, so the dogs have a chance to see and smell each other at a distance.
When they do pass closely to each other make sure you are NOT holding them tight, if they want to get up close and have a sniff, let them. If you hold tight, they will strain at the lead and it makes their body appear bigger and more confrontational to the other dog.
keep casually walking and let them have a good sniff of each other.
Watch the body language, and if there is growling or barking, or you dont like the look of it, then leave and try the next day.
If they seem to be getting along ok, you could let them off in a fenced dog park?
If they get along and are going to bring one to your house have both dogs on lead, and have them meet down the street from your house. Do the same introduction as described above, have them go for a walk together then bring them in the door together.
good luck