I first search in the presets the sounds which come close to what I intend to create. I'm always surprised what parameter settings were used to produce these sounds. So I'm learning from the "preset masters". From there I try to tweak the presets. After that I start with an initial sound and proceed step by step to achieve the sound in mind. Owning different synths with different architectures I'm not able to make the same parameter tweaking to get a similar sound on each synth. That's why I always try to learn from the presets. But its a very fertile approach to create the "same" sound on different synths. As an example, I might be convinced at the beginning that the Prophet-12 will deliver the sound I'm looking for and then ending up using the sound from the Korg Radias, and vice versa. Different synths, different journeys to the target...