That sounds exactly like what I'm trying to do. I have no experience with the agency world and most of my contacts are in giant corporations. Do you think it would help to do some work in the agency world?
I guess it depends on what country you live in; I'm in the US, not sure what it's like elsewhere with regards to advertising, but if USA-based then yeah I would pursue that. Initially it'll probably be easier via a recruiter who already has a relationship with the agency where they bring you in and put you on the bench until a gig opens up.
From what I've seen, brands (clients) rarely do much in-house -- they hire agencies (for periods of time, then will go to others depending upon results), sometimes hire as Agency of Record for a period of time as well (all creative, from web/app/digital through social management, media, print, etc, flows through their AOR) -- everything runs on quarterly client budgets (so frequent initiatives that "ladder up" to XYZ intangible "KPI" -- you'll get used to the arbitrary and capricious lingo) -- and it's really not that far off from a modern version of Mad Men. "Agency life" is another phrase that encapsulates "we probably have time management issues and/or over-commit to stuff, so if you want to succeed in this business, be willing to be patient, present and available for the duration and parameters of the project" -- as a freelancer though, you get paid by the hour, rather than being a salaryman.
I did 15 years of full-time employment, salaried. Overtime === a slice of pizza, a pat on the back, a vague promise of promotion; as a freelancer, it's dollars-per-hour, nothing more nothing less, you get paid for your efforts.
I've only been fortunate enough to benefit from that having done full-time salaryman in these places long enough to meet enough people and make enough contributions to become a known quantity. That said, I do have friends though that were ONLY contractors the entire time, usually via a recruiter as mentioned above, they worked in the same places on the same projects, and they've been able to flip that into similar situations or even full-time with the companies they gelled with the most.
There are a bunch of ways to approach it, but the fluid, always-changing clientele of ad agencies provides quite a lot of opportunities for work that isn't just "employee".
