Murder your darlings

Avoid definitions. Mostly, people can figure out what you mean with little doubt from the context. Only use definitions when you are using a woord in a specific way that does not align with its ordinary meaning.

• • So don't define "tax" as any tax, duty, excise, deduction, witholding impost or lvey imposed by a competent authority any other familiar term that will, you know, show up on the Google as a freaking synonym for "tax".

• Use the active tense. Avoid the passive whenever you can.

• "for the avoidance of doubt". This is an explicit acknowledgment that what you have just written contains doubt. You are a solicitor. You are an officer of the Queen's English. Physician, heal thyself.
• "(including, without limitation ...)"
• "unless otherwise agreed by the parties"
• "and/or"
• "We reserve the right to ..." - Wait a minute: Did you just give that right away? If so, you can't reserve it. If you didn't, you've still got it, so - you know - shut up already.
• ", whether ... or otherwise," - kill it. Go on, just kill it. You'll feel so much better.
• "we may, but shall not be obligated to, ... " - collapses quite happily down to "we may ..."
• "Please be advised/please be aware, please note" - If your counterparty is reading the document, she is being advised, becoming aware, and taking note. If she's not, it won't make a damn of difference.

"The parties agree that..." - you don't say. It being an agreement and everything. Try something novel - don't say it.