One way is to exhibit at a targeted trade fair. This way you get to merchandise your collection your own space and you can meet several potential buyers at the same time. If you do this, you need to contact buyers well in advance and invite them to your booth.
A classic way is to pack your collection samples in a garment bag and invite yourself to the buyers. Their schedules are busy this time of the year so may have to hustle a bit to get a change to give them a private presentation.