Seems like a bit of the data on the PDC is a little old so I'll chime in with some new info.
Beach/Daygame -
Mamitas, Kool, Canibal Royal....you'll find most of the local girls will be up just north of the mamitas beach club between mamitas and shangri-la.
I also recommend spending time at some of the beachfront bars further south during the day.
Checkout Fusion, & Zenzi
You'll find some nice waitresses working there and often this is the part of the beach where most of the argentinian girls will be.
Restaurants -
I recommend using the time you eat wisely. You can often find nice girls waitressing or hosting at the restaurants, and coffee shops. If your spanish is limited it should be ok because they all speak english. You'll have more luck if you can convince them you are wanting to move to playa as most will avoid tourists when hooking up. A good example is Tequilla Barrel.
These are my favourite restaurants in terms of food quality.
Breakfast - La cueva del chango, Chez celine, or Fusion
Mexican Food - try El fogon, or Dona Mary. Dona Mary is a local favourite. Very cheap & good food on 30th and 28th near Mega.
Venezualan Food - Kaxapa Factory
Argentinian Food - El Diez
Seafood - Los Aguachillies
Pizza - La Piola
Quick Snack - Brochetas (near Mamitas) -good for a bite after a day at the beach, Burro Playero
Other Favourites - Oh Lala, Rincon Yucateo, Gluay Maai Thai
Accomodation
You'll find the best value on Aribnb.com.....don't position yourself too close to 12th street as it will likely be noisy.
If you have a decent budget to work with this place is perfect for logistics.
https://www.airbnb.com/rooms/222199
Nightlife
Checkout
http://www.eventsplaya.com to see what is happening when you are there but I've listed below my favourite spots.
Start your night with a drink at Lambassade, Ula Gula, or Diablito Cha Cha Cha.
Focus your nights in Mandala as it's where you will find the best quality women. Lots of Mexicans, Europeans and Scandanavians. If downstairs gets too crazy check out the rooftop bar which can be fun.
If argentinians are more your style a few drinks at Pura Vida is ok but it's not my favourite spot by any stretch.
Finish your night at La Santanera. Best to go there with a girl though but if your spanish is good you'll find more latinas here who can be easy pickings. I prefer the rooftop bar in Santanera.
Get yourself a heytell account if you have a smartphone. This will be the best way to get in contact with girls you meet. They all love it here.
If you find yourself looking for a good spot to take a date check out La Azotea. Cool, upscale bar with nice views over the beach. Best on a Thursday for ladies night.
Things to do
There are a lot of Cenotes between playa and tulum for example cenote azul. Definitely worth a daytrip to check out.
If you are into ruins head to Coba.
Akumal is a cool spot that you can swim with turtles and relax on the beach.
Tulum is chilled and worth exploring for a day.
If you need a car for the day checkout Blueway Car Rental near the Cozumel Ferry for the cheapest prices. Alternatively you can get around pretty easily on the Collectivos to most of the spots and its really cheap.
If you are looking for a workout checkout The gym, or evolve. The gym at the moment has a 30 day free pass you can get. I'm not 100% sure of the conditions for the pass but I think if you can provide them with a local address it should be fine. Both gyms are really nice, well equipped and clean.
Yoga Classes can be a goldmine here for women and are often free. You'll see flyers up for classes on 5th street, at the gyms etc. I can ask around as to where has the most girls if someone needs that info.
Women
It can be hit or miss at night. Some nights I've been out where the ratios were crazy. 3 girls to every guy....some nights its the opposite. In the past Sunday nights have been my favourite but it seems to change almost every week here.
If you can lock down a girl before heading out at night your life will be easier. Try daygaming in the restaurants, beach clubs and cafes. It will be harder for you with the locals (as a tourist) but i recommend letting them know that you really want to move here so they view you differently.
The argentinian girls are definitely easier here than what you would find in argentina. If you can pull of the surfer look you'll have an edge...they seem to get excited for that.
The backpackers and overseas tourists usually end up in Coco Bongo, Coco Maya, and Blue Parrot at night. If this is your style then go for it but you wont find any high end latinas there.
As mentioned by el jefe avoid the israelis - not worth the time.
If you are planning on coming to Playa Del Carmen you'll find it good for most of the year. I've seen it best usually around December and February. Avoid coming here in January especially during BPM Festival.
Got any questions happy to respond.