When Im layering an pad, an lead or some synth, this I do often: I found one great main lead. Then I take another lead, blend it and so maybe at least two. One pad I used four diffrent pads into one "sound". Then I bus them out, by using compression, light eq, some distration, imager, reverb and little delay. Sometimes I use an phaser to get the sound. When I feeling the lead, then Im done. But its one method I will use.