The Sims 3

When people really want to get the achievement in the fastest way possible, do what I did (only do it this way when you got all other achievements out of the way and need more than a 100 wishes completed).

All credits go to Askeroth, who posted this on 360A.

Make a new household, consisting of 6 adults. To speed this process up, make one adult and make 5 copies of him/her
(preferences doesn't matter at all). The only thing I did was giving them a number instead of a name, because 6 lookalikes can be very confusing.

Next go to a new house and buy it without any furnishing. After that sell all what is left in the house (toilet, bath, stove and fridge).

Next go to the options menu and disable free will.

Start playing the game and fastforward it. Don't get any wish and wait a couple of ingame hours. After about 10 ingame hours all your sims get the same wishes; they want a toilet, a shower/bath, a fridge and/or stove and a bed.
Accept all those wishes and save afterwards on save 1.

Next buy all the things your sad sims want. You'll get 24 wishes completed in one go.

Save your game on new save 2. Quit the game and load save 1. Rince and repeat. Just make sure you always make a save on no. 2, so you can load your original save.

It took me little over 3 minutes to do this, once the original save is made. That's about 450 completed wishes in a hour.

* Also added the stove, as Channel 8 News experienced it, while doing it this way.

I found a quick way if you want to just get this achievement and don't really want to play anymore:

First, I'd recommend getting EVERY other achievement before going for this one. You can work on getting wishes while whittling down the achievement list, netting quite a few in the meantime.

Next, get as many of your household to have as many easy, quick wishes on hand as possible (aka "Pickup [baby]", "Buy [furniture]", "Chat with [Sim]", etc).

Now, save your game. Then, quickly complete all of your Sims' wishes and any that come soon after. Usually, after completing the wishes that are on hand, some more that I can easily follow up on come soon after and I go ahead and do these too. Once you feel they aren't coming anymore, save your game, but this time in a second save slot.

Now, the thing here is to then reload the original save file, go through the wishes again, and save in the second slot. How this works is that the completed challenges and progress on them is saved to your gamertag when you save, not the file itself. So, as long as you're saving, you can just keep stacking the wishes. Works for "Epic Fail" too.

All in all, this is quicker than playing the game normally. During my grinding, I was able to jump in and get around 7-10 wishes each game load within 6-8 minutes, depending on if more wishes popped up or not.

Wishes are things that your sims want to do and can be compared to small goals. They are short term things that your sim would like to accomplish such as eating a certain food or talking to someone. A notification will come up on the top right corner of your screen when your sim has a new wish. Push RT to read the wish and what it wants you to do. To accept it push A and to decline it push Y. You can have a maximum of four wishes at one time so if you get a wish when you already have four you can open up the main wish screen by pushing and you can change which wishes you want and which wishes you don't. Note that once you decline a wish or get switch out one of your wishes you can't undo it. The type of wish will come up again but you'll just have to wait so pay attention when managing wishes. Also note that you must have the wish active for you to be able to complete it. If a wish is on standby and waiting to be switched in you can't complete it until you make it one of your four wishes. Once you complete your 1,000th you'll get the Achievement.

There are a few good ways to get wishes quickly. One requires some very specific traits but if you don't have them you can always buy the "mid-life crisis" lifetime reward for 20,000 lifetime happiness points. This method requires you to have learned both the guitar and logic skill, it requires a romantic interest and it also requires the following traits and lifetime rewards.

-Neat -Trait
-Genius - Trait
-Hates outdoors -Trait
-Party animal - Trait
-Charismatic - Trait (not required)
-Legendary host - Lifetime reward (not required)

When you have the necessary requirements in place throw parties whenever you can. During the party you'll be bombarded with wishes and you should complete at least 10 by the end of each party. At that rate you can get a lot of wishes per hour. Credit goes to darkconsoles over at the sister site for this method. Along with this you could do other things to help such as setting the traits of your housemate to slob and also if one of your sinks break don't repair it, you'll be given the wish "mop the puddle" all the time. I found that you have parties at least every 3-4 hours(sim hours) If you have legendary host, throw a party, invite one person, when they arrive ask them to leave, you automatically throw a great party and you'll still get all the wishes like "Play the Guitar", "play chess".

Another method to getting wishes quickly is having children. If you have a family oriented sim with an infant in the family the sims is going to get loads and loads of wishes having to do with the care of your child. They're easy things too like snuggling your baby or buying them toys.

I saved this achievement for last for obvious reasons and by the time I got here I only needed 300 wishes. I also still needed The Reviler, which I also saved for last to use for this strategy. It's not necessary, but it just worked well for me to do it this way.

I started a new game with 2 Sims and I made my Sims have traits that caused them to be workaholics and neat-freaks. This way they never got stressed out when I continuously pushed them toward goals. Also, they always wanted plenty of short-term goals like "make the bed", "take a shower", "clean the dishes", etc. Also, as you earn lifetime rewards, it helps to get things like "speedy cleaner" but I didn't get "steel bladder" because every time they peed on the floor they would get a wish to "mop the puddle".

I gave my Sims jobs that have opposite schedules. The sim that I was not using toward the Reviler achievement, had a day job. This way I was never wasting time watching them both sleep. If you want to have 3 sims with non-conflicting schedules, go for Business (day), Chef (evening), and Criminal (nights).

Lastly, if you stop getting short-term goals, go buy something, like a chess table. Suddenly, your sim will want to "buy a telescope", "learn logic skill", "take a class", etc. If your cue is full, always replace any long term goals with short term goals, but never leave a space empty. The game seems to know things that are about to happen, like "getting a raise" so it's better to have a long-term goal, than an empty wish slot.

If you are good at multi-tasking and need more wishes just double or triple your Sims. Just by using 2, I was able to get the game completion in about 5 hours, as I had already completed the other 48 achievements in advance.

Sims with neat, clean freakish traits will get loads of wishes for making the bed and mopping up puddles.
Then just have a couple dishwashers and sinks and don't repair them when they break.
Your sim will almost constantly clean up puddles and then immediately want a shower and clean the whole house for 3 quick and constantly recurring wishes.

Have a house of 3 people who like to socialise and are all clean freaks and you can get this in about 8 weeks (sim time not human)

Just give your sim either the neat or neurotic trait and they will wish for things like "making the bed" every day, washing dishes etc etc. That way you can get it without actually having to do anything to complicated.

Really playing with a few neat sims until you get their lifetime wish should make this come easily just in a normal game progression.