The biggest mistakes that business owners make in acquisitions fall into two obvious categories; those made by sellers and those made by buyers. For a seller, the biggest mistake that they make is disclosing too much information too early at the wrong stages without proper advice within a negotiation strategy and without having a confidentiality agreement in place.
The other big mistake that sellers frequently make is involving their attorney too early and instead relying on their tax accountant or their CPA, the person who prepares their numbers such that the terms of the sale of the business are already discussed, already struck before the attorney is involved and can properly council the seller on how to best maximize their purchase price.
For the buyer, similar but kind of flip side problems occur that can crater acquisitions. Not having the attorney involved in early, allowing the other side to draft the non-disclosure agreement, allowing the other side to draft a letter of intent; all of these things can create a letter of intent that is difficult to get out of and ends up not capturing the deal in the way that you need it captured in order for that acquisition to be profitable for you.