Think of it this way- you're either paying them up-front with your time and work or they're paying you up front with some cash.
As somebody who has been burned badly by somebody who didn't pay up after work was delivered I can tell you do not ever work before getting some fee up-front (preferably the entire amount). If the person can't afford to pay you before you start, you probably don't want them as a customer.
Conversely, those who are ready, willing, and able to pay are the best and most lucrative customers to have (and you can charge a lot more than $2300 for your services).
Yes. 1/2 upfront for smaller projects, 1/3 for larger projects is the standard.
For ongoing projects that you bill hourly instead of fixed cost, try to do retainer instead of invoicing and then getting paid a month later model.
Cash flow is THE single most important thing in this business. Try to get paid as early as possible, and delaying paying others as much as possible (while still paying them reasonably soon, of course - just try to negotiate better terms upfront, i.e. get paid Net/15 and pay others Net/30).
Also, never EVER work without a contract. For every project, have client sign MSA and SOW. I bought mine from here: http://msabundle.com/ and modified per my needs.
Yes, definitely. I just did that for two projects in the past week; but it was 1/2 up-front. Albeit, they were close referrals. YMMV if it's potential customers who don't know you.
Oh, definitely. When I was freelancing, I wouldn't start a project without a 50% deposit. I also made sure that 50% was enough to cover my expenses and sanity.
Unless I know the client well, I get a 20 hour retainer up front (which is about as much as I usually bill any single client in a week unless I really like the project.) I send them a bill every week, and while I'll give them a little credit on getting it paid, I won't go more than a week without getting the retainer paid up unless we've got some history.
Sometimes you have to be firm on it, but trust me, beats the hell out of trying to collect 10-15k in outstanding invoices when your mortgage is due.
Yes. A client that doesn't pay up-front doesn't have any skin in the game. It makes it easy for them to walk away.
Also it serves as a negative filter, weeding out cheap or incompetent clients. Like any other business, finding good customers is vital to your flourishing.