Most commercial accounts (property managers, HOA, a big accounts) seek new bids in the fall. They are setting the budgets for the upcoming year. So if you want a particular commerical account just ask them "When do you request bids for the upcoming contract?" Expect they will say in the fall, like October. Then ask them to place you on their list of contract bidders to be notified. They will be polite and say "okay." Regardless put them on your tickler file to send them info or do a follow-up in the fall.
Remember commercial accounts operatate on a budget, just like you should. So they want to know what their landscape costs are going to cost in advance of the beginning new year (Jan).
In the event you see a shabby commercial account and offer them to do it better, it is not like they can just cancel and switch to you in May or June' since they are typically on contract with the current provider.
The only accounts you are likely to pick up during the spring and summer are accounts where the current (& usually 1st season on the property) LCO is doing a lousy job or royally screws up.
For commercial accounts hook up with property managers. Find out the name of the major managers in your area. Look up their address in the telephone book (and then stalk them)... No kidding, but do drive by their homes. Is it well manicured? Is it in a nice neighborhood. Go by on Sat and see if they are doing their own lawn or if it looks like they use a service too.
My best commercial accounts came from a property manager. AND I serviced their personal properties too.