This is a good summary of advice and key issues for any founder or manager who doesn't have a lot of experience in deal negotiations.
Some of the points listed here are particularly important, such as always draft the first version of the agreement or taking the time to understand the deal dynamics.
An absolutely fundamental principle of almost any negotiation is that you (or your lawyers) should prepare the first draft of the proposed contract. This lets you frame how the deal should be structured, implement key points that you want that haven’t been discussed, and gets momentum on your side. The other party will be reluctant to make extensive changes to your document (unless it is absurdly one sided), and therefore you will have already won part of the battle by starting off with your preferred terms. Having said that, you want to avoid starting business negotiations with an agreement that the other side will never agree to. Balance is key here.