Here's what I did, for what it's worth.
I started out with residentials, but quickly moved to commercials that pay YEAR ROUND. And the ones that didn't, I got them to divide the payments into 12 months, so I get less per month, but get paid for the 5 months over the winter for doing nothing but picking up cigarette butts and trash! 3rd year in biz. I've given all but 2 of my resis away, probably 15 or more just this year, to people I TRUST to do them a good job. I've got all I want. Get you a 60 inch Z with a MULCHING KIT...saves SO MUCH in having to clean up crap and keeps from throwing grass in beds, etc., and SURELY make sure it has a foot-operated deck lift assist...trust me on that one. A 60 is REALLY practical for both large and small areas...it's really good for all around. Get a STRONG backpack blower (Shindaiwa EB802) and it'll save you a TON of time cleaning up stuff, before and after you cut...NO raking for me. I ain't doing it! (unless it's to rake up a small amount ot stuff to put in a trash can). And this has been most important...it's made it where NO ONE wants to get rid of me. Everything I cut...NO ONE even puts it out for bid...they just give it to me automatically...I LOVE the security that brings....just by doing this: Do WHAT you say, WHEN you say, do it BETTER than they expect EVERY TIME, and if you get hung up, CALL THEM and let them know why and when you'll be there. Go by and talk to them, just to make conversation, even when you're not cutting. Make them FRIENDS. Do some stuff for free...such as if it doesn't really need cutting, but there's some stragglers here and there, unload the Z, run over it real quick, let them know that "you hated to waste their money when it really doesn't need trimming and stuff and you just knocked it down and there's no charge". I usually bill after 2 cuts, and most times, on the small stuff, I'll cut it 3 times at first, and tell them I'm only billing them for 2...the first one is on the house as a thank you for giving me the opportunity. When you weedeat, leave NOTHING standing...NOTHING. And blow everything off TOTALLY...even any clippings that are close to the doors so they won't track it in the house, etc. If you do these things, it'll come back to you 10 times to the good. And they'll NEVER want to get rid of you, because they know you give a darn, and they really appreciate you being honest and fair with them. Doing this will make you stand out from every other jack-leg or big outfit out there that just cuts whether it needs it or not, and bills for every little thing. That's how I built my biz...going up and above what they expect. It's WAY worth it on the long run. Just my two cents worth. Hope it helps.