Every project manager I have ever met has a different approach. Even if you follow Agile, or Waterfall, or a hybrid, there are little tweaks everyone makes. The approach I have found works best is a Hybrid Agile method. Working in agencies, means you have clients.This means sign off points are needed. As much as I wanted to get clients involved in the day-to-day work, they have other things to do. True Agile only works if you have every stakeholder involved in every decision daily. So with this in mind, my approach is we work to an Agile approach internally, commit to daily stand-ups, team collaborations and an iterative process that evolves every single day. But, I add in milestones in each stage of strategy, design and development, to have approval points for the client. This timeline MUST allow for amends, but it must also be a very quick turnaround, so that each sprint is not delayed.