So in the fall, I make those individual pieces that I can blend and put together to create what I want to drink. Experience (trial and error too) has helped me focus on what kind of pieces I want to produce in the first place.
Deciding how ripe I want the fruit and picking a harvest date, how I'll press the fruit, skin contact or not are some of these decisions. Than what yeast strain (if any), what fermentation vessel, lees stirring; all these are factors that will effect the final product or piece if you will.
Fast forward 6 monthes, all those decisions are in the forefront of my tasting as I get ready to bottle in the next month. Now its time for blending
Start by pulling out little bottles of all the vessels/batches. I create small sample sized different blends, around a 100ml. Lots of precise measuring and percentages calculated. Cylinders and bottles, pouring and spilling. Usually a mess ensues. Mixing everything 7 times to blend the different densities. I than taste them immediately, then let them sit for a few hours. Taste again. Always standardizing the way one tastes is important, remove the bias. Smell, swirl, smell again. Sip one. Spit. Sip two - hold. Spit.
I select the letters I like, and try the same blends in week or so. Just to make sure I'm happy with it before blending the final larger batch of wine.
Cheers!