1. Use "said" in the most superfluous ways possible. Bonus points if you can use "said" more than once in a sentence without talking about dialogue. As in: "The Plaintiff executed said contract by appending his usual and customary signature to said documentary exhibit, referred to hereinafter as the documentary exhibit." Using "said" many, many times will imbue your document with legal magic, letting you charge far more than is usual for this work of literary genius. Clients may assume that without the said "saids" the document might have been invalid, or at least be far less scholarly in nature.
2. Write out all numerical references in both words and numerals, so as to be as redundant as possible, and risk having the words and numbers not match, thus creating many subsequent work opportunities for solicitors to render legal opinions on those discrepancies, and barristers to seek judicial pronouncements on such discrepancies. As in: "The purchaser shall pay One Hundred and Twenty Seven Thousand Dollars ($1,270,000.00) in Canadian currency to the seller in exchange for title to said land."
3. Utilize as complicated word and sentence structures as possible, as clients will be impressed that you're able to figure out the meaning of the documents you're creating since they can't possibly follow the meanings themselves. As in: "The party of the first party, hereinafter the First Party, and hereforeto the sub-leasee, in the above-captioned matter..."
4. Write "WITHOUT PREJUDICE" at the top right of every letter or other document you create. This will imbue the document with magical qualities even greater than those created by the superfluous use of the word "said," so that you can say whatever you want, and it will never be held against you. It will be like the document is the Invisible Man, both there and not there.
5. Write "DO GOVERN YOURSELF ACCORDINGLY" at the bottom left of every letter you create. Make sure it's always all in capitals and in bold. The capitals and bold are vital, otherwise it won't legally work like it's supposed to work. Closing your letters with this, instead of or in addition to the boring and prosaic "Sincerely" or "Your truly" will compel people to do whatever you're asking of them in the letter. Even if they don't want to do it, they'll feel unable to stop themselves. Demands for payments of money. Demands to do or not do something. They'll all be met with a cheerful smile if you use this age old legal phrase.
As a longstanding teacher of legal writing, and fan of the plain language legal writing movement, it pains me that even new young law students continue to believe that the features I mention above make them sound more like a lawyer, or worse still that broadly using such words enhances legal results. It's been a long personal journey of recovery for me to rid myself of such habits, and it can still be a struggle to resist the impulse to sound lawyerly.
We should all be asking ourselves in our lives, and in our writing: "do I really need this thing, and what purpose is it really serving?" If we can come up with a good answer, then by all means keep it. But if the answer is "I don't know," then some further reflection is clearly required.