MONOPOLY DEAL

The description is pretty straightforward, so I'll just mention something that caught me out twice while I was going for this achievement.

You can't use the "Double The Rent" card if you use the rainbow Rent card. You need to use one of the Rent cards that is half Dark Blue.

However, you can have wildcard properties for the blue set.

Hope that helps.

To get this achievement you have to have Boardwalk and Park Place down with both a house and hotel on top. After you must have the rent card with the blue/green on it and the double rent card. Use the rent card on this collection and than it will ask if you want to use your double rent card, use it. Achievement will unlock after doing this. If boosting for this as I am sure most will be, the person that was helping the other person get this can use the card to steal the collection from the person that just got it and they will get the properties as well as the house and hotel, than they just need to get the 2 different rent cards. Please keep in mind when playing that any card you cash into your bank will not come back in the card pile, so any cards that are needed have to be discarded back in the pile so they can come up again.

STRATEGY:
When you start the game this achievement should be your main concern. You will get most of the others trying for it. It is mostly luck based but without a strategy you'll miss your opportunity over and over and over again.
You will need both Dark Blue properties whether legit or with Wild Cards, a House, a Hotel, the Double Rent and the Green/Blue Rent cards. Multi colored Rent cards do NOT qualify.

Play a local match against just one Easy AI. Getting the Dark Blue cards are the least of your worries. Keep restarting the match til you have at least 2 of the buildings or Rent cards.
Don't try to win. Prolong the match as best you can. In the beginning focus on having money in the bank and stifling the AI so Rent doesnt decimate your property cards. Don't put down a Blue property til you have a plan to put down both at once or the AI will steal it. It will take a minimum of 2 turns to get the kill move for the achievement probably three turns though unless all 6 cards are in your hand. Make sure you have enough moves left to add the Double Rent to the Green/Blue one or the opportunity is lost.

Keeping 6-7 cards in hand seems to work best, holding onto cards the AI needs to win. Discard the cards he needs instead of playing them so he can't steal them. Try not to allow enough cards for a set even onto the board.

Having spent all day on this achievement, against a single "Very Easy" bot, I noticed a few things that changed how I went about unlocking this achievement; as soon as I changed my strategy, I unlocked it on the second game.

Firstly, I took note of a few behaviours that appear in a match against a single "Very Easy" bot:
- I always seemed to get the necessary rent cards; but my opponent would always get the hotels. This took some time to identify, at which point the game was a bust and I would restart.
- I always seemed to get at least one Deal Breaker - and my opponent would never use or counter them.
- My opponent would put down one or two of each property type, as available; they would not build property sets until much later in the game.
- Once my opponent did have a property set, they would almost immediately place a house and a hotel down. Ironically, they would never charge me rent.

I realised that the way to go was to force my opponent to build the blue set up for me, before stealing it with a Deal Breaker and immediately charging Double the Rent. Here is the strategy I employed:

- To start with, I wanted both the Double the Rent and Green/Blue rent cards. Note that you can not use Double the Rent with a wild rent card; it has to be a Green/Blue rent card. Restart until your initial hand contains these two cards.
- You want to keep yourself at seven cards, so that you can return cards to the deck by ending your turn above seven cards and choosing specific cards to discard. By discarding these cards, we have another chance of our opponent picking them up and using them.
- As soon as you receive a blue property card, play it. You can play other properties, but do not build sets. I was lazy, and just kept a single blue property in play. Return any other blue or blue/green wild card you have to the deck.
- Hold on to a single house card; you might get really lucky and also pick up a hotel card. If this happens, just move forward with building the set, yourself. We return all other houses to the deck by ending our turns with more than seven cards in our deck and choosing to discard the excess houses. This way, there is more chance of our opponent picking them up.
- Hold on to Sly Deal cards, and use them to block your opponent from building other sets. Don't touch their blue property, railway or maintenance cards. We don't want them using their house and hotel cards on non-blue sets - you can't use these cards on railway or maintenance sets, so they can be left alone.
- Hold on two Forced Deal cards, and as soon as your opponent plays a blue card, use the Forced Deal to trade one of their other cards for your blue card. This will force them to complete the blue set, at which point they should almost immediately try and place a house and a hotel down. Hold on to the second card only if your opponent has not placed a blue card, already, as you might end up drawing both blue property cards and having to trade them both.
- Use Pass Go cards whenever you can, even when it leaves you with cards to discard at the end of your turn. We want to go through the deck as fast as possible.
- Bank all other rent cards, as well as the duplicate Double the Rent and green/blue rent card. You also want to bank any money, as well as the It's My Birthday and Debt Dollector cards; this just removes these cards from the deck, so we can go through the deck as fast as possible.
- Hold on to a single Deal Breaker, and bank the other, should you draw both. As soon as your opponent builds the blue property set and adds a house and a hotel, steal it with your Debt Collector, and charge Double the Rent.

As long as you keep your opponent from building other sets, and you don't get super unlucky to not draw a single Deal Breaker, you should have this done much faster than trying to get all of the cards, yourself. This is even easier if you just play a friend in multiplayer, and have them help you rig it; but if you don't have the time for multiplayer, this strategy should be the way to go.