When i rout PCB at first i place big elements and make trial rout for understanding how to do this board and problems that can rise. After several trial variants i place resistors, capacitors and other small elements and make full rout to the end.
Once Before we fix the stackup we route signals to analyse the routing flow with some impedance- We call it trail route
After Stack up being fixed, we used to route it exactly based on stack up(impedace)- We call it detail route