I hear people talk about exit strategy.
what are the common exit strategies and their guidlines?

Exit strategy depends on the assett class. Land,multifamily,development,retial,industrial,hotel,etc.,etc.

Each assett class has different variables to deal with and requires a different approach.

Exit strategies are basically having a plan A,B,and C.

The first part of an exit strategies is knowing who your buyers would be.

Example for a new build it would be pension,insurance companies,and reit's for class A space.It could also be one of your joint venture partners wants to be cashed out upon completion of the build and you buy them out.

You could buy a apartment building rehab,and release up at higher rates for increased cashflow and then resell fo rhuge profits.

Basically with any structure you can keep it as-is,build something completely new there,add on to it to change the assett size,and you could also change it's use to a higher purpose based on the demands and needs of th ecurrent market.

Example you find a building in your area to purchase.You notice it's a two story office building in a great location however it is run down. You drive around and notice the area is SATURATED with new office buildings and competition is tough.

You notice with the growth however that there is a need for more retail space and demand is strong. With this you apply to change the buildings use and retrofit upon purchase as a condition of the purchase.

The value is always created in the deal on how you are abel to get your money out. You want to do plan A which gets you the most money but sometimes yo uhave to go with B or C with less profit.

Super Realtor offers some good insight. There are a couple more things to keep in mind regarding exit strategies.
If you are applying for short term financing(hard money,bridge, mezz) and your exit strategy is to sell the property to pay off a balloon you will have your work cut out for you. Lenders do not want to get stuck with a property or have their funds tied up because you can't sell the it due to high inventories, declining values, etc.
The term exit strategy can also mean you will refinance the property down the road. This could be for many reasons. You can obtain conventional financing at a later date, you plan to rehab the property and increase it's value and therefore decrease the LTV, etc.