I use the rental prop. calculator in BP to evaluate properties and I love it.

Once you learn how to evaluate properties for resale or rental, you can pursue whatever your end goal is.

Use the existing rents for evaluation - - they're real and all your marketing may not yield improvements.If there's known vacancy issues, then adjust the the GSI (sum off all rents * 12 months) and subtract the loss rents from vacancies (number of units vacant * average rents * number of months their empty) . 

I am currently evaluating a monthly cash flow of $1300.

Ok, now that you have taken your initial step, below are some quick links to get engaged.While you wait for feedback from turnkey property owners I added the below blogs on turnkey investing that you might find useful.https://www.biggerpockets.com/renewsblog/2015/08/20/askbp-089-how-do-you-evaluate-a-turnkey-company/ (Turnkey Evaluaton)https://www.biggerpockets.com/renewsblog/2014/03/23/what-does-turn-key-real-estate-business-entail/ (Turnkey REI) http://www.biggerpockets.com/startherehttp://www.biggerpockets.com/meethttps://www.biggerpockets.com/alertsHow to Use @Mentions on BiggerPocketshttps://www.biggerpockets.com/ruleshttps://www.biggerpockets.com/termshttps://www.biggerpockets.com/inviteshttps://www.biggerpockets.com/perkshttps://www.biggerpockets.com/forums/categorieshttps://www.biggerpockets.com/rei/glossary/https://www.biggerpockets.com/webinarhttps://www.biggerpockets.com/courses/a-beginners-introduction-to-real-estate-investing (video courses)https://www.biggerpockets.com/real-estate-investing (Ultimate beginner's guide to REI)REI can be very daunting, but, before you go searching for that 1st buy, please take a few minutes to bone up on the tips in link below.https://www.biggerpockets.com/renewsblog/2014/12/19/real-estate-investing-success-smart-tips/REI books suggested by BPershttps://www.biggerpockets.com/renewsblog/2015/11/13/7-real-estate-books-beginner-investors/ (7 absolute must read books for beginner REI)http://www.biggerpockets.com/renewsblog/2013/04/14/best-real-estate-books/?

.*** GRM is strictly a function of Revenue, where as Cap-Rates (my preference in evaluating a deal) takes into account Operating Expenses ("OpEx").I think this is especially important Connecticut where OpEx can be high because of 1) high taxes [especially in Bridgeport], 2) the majority of properties are old (requiring more for both reserves and ongoing repairs), and 3) the high cost of labor/service contracts in the state.That being said - and somewhat contrary to the above - many commercial brokers in CT of mid to large multi-families typically trade properties on a price per unit basis (and the price will fluctuate depending where in B-port).

One of the important things to learn is you local market, You do that by looking at and evaluating lots of deals.

Can any of you help in evaluating 20 acres (2-10 acre parcels) in Malibu!

I feel very good about what they're doing and how they have helped me evaluate the areas. 

Thanks for the evaluable input!