How does one position themselves to get strategy work in a MC firm as opposed to others?

In my experience: build a reputation for being very good/the best of your level and you will become the go to for a couple of seniors. Make sure those seniors are ones winning plenty of interesting work. Personally this has taken approx. 8 months, now I am effectively choosing what projects I go on and who I work for. The staffing on my office is very network driven and the resource planner isn't very visible.

Just crush everything your given, deliver quality beyond your level, take ownership of the project/work stream no matter how small a role your given. By this I don't mean be possessive, be proactive checking in with managers on its progress, is it on track, does it need more resources at short notice, can you take some pressure off a colleague that's staffed on it, do you have a hypothesis that you think will improve impact and not chew up time. Work to your strengths, early on this will be making ppt and excel, be aware of your weaknesses, probably don't know a huge amount about a topic/firm methodology - clients know when your full of shit so keep your contributions in check and don't try to be a hero. Be modest, the most hated people in my office are those that think they are legends.