first I personaly need firm concept,a detailed plan about each element of tune and how will it work,from little shaker so low in volume you wouldnt even conciously notice it to upper harmonics of sub bass
actualy I plan in my head each harmonic of each synth in way so it will never fight with other synth,for example if you have reese with saw waves tuned +- 25,then if you fit neutral square wave to it,it will work nicely becose the harmonics of reese are +-25 away from harmonics of square..... so thats the reason the square + reese combo is extremly common,becose it sounds good and its also flawless on technical level
first thing I do is kick drum,and then I will make sub bass and fine tune loudness of the two,that gives me firm values around witch I make everything else,the definite loudness of sub is super important becose its the element that takes most headroom,one thats always to blame when something starts clipping,