To be successful in real estate investing, you must effectively analyze the cash flow and cost projections of that potential new project. It is essential to understand the potential pitfalls and possible upside that would cause you to have interest in investing your valuable time and treasure. Without this practice, you can never understand what opportunities are worth pursuing. However, be aware of the hole could potentially find yourself falling into when drowning in numbers, spreadsheets and considering all the different scenarios. This creates "paralysis by analysis."
It is similar to shopping for a new car or a new television (except for the minor detail that we are talking assets, not liabilities). You are taking into account at the different property features - how many units, how many vacancies and occupied, market & current rent, square footage, mechanical ages, roof condition, crime, demand, lease terms, utilities paid by owner and tenant, maintenance actuals and projections, lawn care, asking price vs comparable sales, cap rates, cash on cash projected return and more! The list can get quite long and your brain can get tied in a knot if you're not careful.
My suggestion is to think through your strategy and focus on the benefits sought to achieve your purpose through real estate investing. Know your competition. Know your seller and the results they seek either through profit, problem solving or exchange. Know your numbers but don't get married to them so much you miss the opportunity that sits in front of you. Historical numbers may be fairly representative of the future but will not always hold. Focus on how your ownership will improve those figures. Control the controllable. Get in the game. Over-analyzing could get you in a position where you never make a move! Don't let it happen to you.