Bonus Tip: The ‘4 for 2’ achievement trick!
Grab a friend who plays this game (or add someone who does) and between the two of you, you can grab all the following achievements pretty quickly:
Partners in Crime (20)
Play a contract created by a friend
Contender (20)
Participate in a contract competition
Competitive Spirit (20)
Create a contract competition
Thumbs Up (20)
Like a contract
Here’s how to get them all fairly quickly. Each of you go into contracts and create a contract. The easiest way to do it is to have your contract start in the first part of the mansion, you’ll basically be just outside the kitchen, and the only guys around are one guard and the chef, if you set one or both as the target you can literally just pop them, turn around and leave. Once you finish your contract you can select ‘Create a competition’. The only thing you need to change from the default settings is inviting your one other friend, that will pop ‘Competitive Spirit’. Then, when your friend send theirs, play through their challenge (hopefully they do an easy one to) to get both ‘Partners in Crime’ and ‘Contender’, but before you hit ‘Continue’ after the map, hit Y to ‘like’ it. That should net you all these achievements nice and quick.
(Edit: sorry for not embedding the achievement tags, I'm not sure how to do that. If somebody who sees this wants to message the method to me or leave it in the comments, I can edit.)