This advice is good for the UK too. Yes it is dysfunctional
However it is a pretty simple one off step to incorporate, which your accountant should handle easily for you. After that optimise to maximize cashflow, and don't get excited about other tax savings. Some people get bogged down trying to save little pieces of tax by, for instance, buying assets they don't really need. Optimise for best cashflow. Optimise for best cashflow. There I said it three times. I am a finance professional who has held fc roles. I think about tax very rarely. I think about cashflow constantly.
Optimise cashflow for consultants:
Charge more
Charge up front
If you supply anything make a margin on it, and get paid upfront
Bill on time
Bill on time.
Seriously stop working and write your bill out. A well functioning finance department at the client will pay all authorised invoices around the due date. Authorisation takes time, get in the queue early.
Chase your debts immediately, if you have large bills due for payment call your clients accounts payable (know who this is) and ask them if they have the bill and ask them to confirm what date it will be paid on and the amount. Send statements too. I see this every day, where someone is waiting for co to pay them but co has no record of the invoice, it is in spam, in the wrong persons inbox etc. AP departments don't mind being chased, they expect it, it is their job, don't be shy!
Copy your bills directly to accounts payable as well as your direct contact. AP are generally good at chasing internal people for things they know about