Hi. great question!
I've owned and run a digital marketing agency since 2007. In it's current format it's focused on Adwords and I've a team who run it day to day, with me in a managerial / hands-off / advisory role. Catching up with them on key projects once a week.
Since 2007 we've done a bit of everything, bar web design (dabbled but so totally different from delivering ongoing marketing activity that I'm glad we never really got into it. And by "totally different" I mean the sales funnel, the delivery, the skills, the client involvement - everything!).
We've now drilled it down to Adwords because it's core skill that only a few people have. and it's what we've always done really well for clients.
So to properly start answering your qs:
- don't bill by the hour - fixed fee, monthly retainers are all good. Very few businesses are doing well with commission - the only time I've done it everyone ended up annoyed.
- first real hire - someone who can do the stuff you (a) don't want to do anymore (b) that it's not worth your time to do (c) solves a problem. So it all depends on YOU, what YOU want to do, and what your clients need.
- but - day one - outsource your bookkeeping (dealing with the money, and chasing it in - it's not very expensive, it means it will happen, AND (most importantly) it means you get focus your relationship with teh client on building great results, they don't see you as the guy who shouts at them when they don't pay up on time.
- I'm a big advocate of going to an expert. It's now very hard to be up to date on pracitcal application of all the marketing methods (a full time job in itself) so focus on what you're/ your team are good at. I personally would avoid "SEO"(whatever that means these days), and site dev unless you're going to specialise in one of Shopify / wordpress etc
- recurring income - first step, chose a service to deliver that plays into a recurring model. ie we do adwords because it needs to be optimised every month, and all our clients are on a set monthly fee under a 12 month+ contract. Graphic design does not give you this!
- personally I wouldn't really outsource anything that's delivered for your clients. Apart from admin-y stuff. The occasional research project on Upwork, phone answering, and graphic design bits if you really have to. The core skill/service you're delivering should be delivered by your team - otherwise you're just selling project management...
- to keep clients happy. As soon as they sign send them a physical gift (book / wine / chocs etc) it's going to be a while before they see results so a tangible thing really helps! Do what you promise you will - if you say they'll get a report each month, give them a report each month. Have regular catch ups (every month or so) on the phone / online calls etc. Meet F2F when you need to / every 12months, more often if they're spending more!!
A little bit of a brain dump but I Hope that helps!