Real estate is a highly competitive industry and there are many mistakes that can lead to a loss in profits. One of the biggest mistakes is failing to properly research the market and potential properties before investing. Another mistake is not understanding the current market conditions and trends. Additionally, not having a good understanding of legal and financial aspects of the transaction can lead to costly errors. Lastly, not having a plan for marketing and promotion can cause a property to remain unsold for a longer period of time, leading to a loss in profits.