I am not sure if you can breed blue and gold gouramis. All I know is that they are both the same species (I think), just different color varaints.
First, find a male and female. I am not sure how to sex them, but IME my gold female gourami was a dull yellow/gray and very big.
To condition them, I would feed them some bloodworms, and then keep your water pristine and provide many hiding places. Then wait.
After you see your male building something that looks like soap spilled in your tank (a bubble nest), you have a pair. Now, this is when you have to be careful. After they court each other, you will need to take the female out. If not, you're going to have a lot of aggression problems between the two. The male is going to attack the female, and unless you have several hiding places and your tank is heavily planted, she'll be stressed.
After that you should have babies.
This is all purely opinion. I haven't tried to breed gouramis and have just been going off one my experience on DGs breeding. Good luck!