A rather simple but time consuming achievement. The game essentially will hold your hand the entire time, letting you know exactly where you need to go and what you need to do next to progress the story along. Note that the difficulty achievements in the game DO NOT stack so you will have to play the game through a minimum of 3 complete playthroughs.
Also, the trading cards that you collect in one playthrough do not cross over to your other 2 playthroughs, so don't waste your time trying to find all trading cards in the easy playthrough, unless you want to knock out the trading card achievement first. I collected all the trading cards in my first normal playthrough, so when I had to basically delete my old game to start a new game, I was quite disappointed. Thus I would recommend saving your card collecting for your last or hard playthrough. That way you can keep all of your unlocked content which will help dealing with the more resilient enemies that you will face on the hard difficulty.
The game on easy is basically a breeze but since you must play the game 3 times it's best to try to fnish the game as quickly as possible. Here are a few tips that can help make it easier and faster:
1.Get the radio from George in Ch. 2! The radio is a must as it will save you A LOT of time. With it you can travel anywhere on the map you have already been instantly, rather than have to drive everywhere in those crappy cars. This requires you to do his quest. To do his quest you must find his lost dumbell in the police station and give it to him, which is in the kitchen. Then find a nameless flower for him and deliver it to his house. The flower appears on rainy days on various parts of the map. A flower icon will appear on your map to let you know where.
2. Get the infinite SMG. You can get this by completing Keiths first quest in Ch 6. Talk to him and you will be able to get a map from him. Go to the location highlighted on the map and fight through the enemies until you reach the end.
3.Get the Wesley Special. This one will require you to get all bones scattered throughout the map. Once you collect all the bones, give them to Brian in Ch 8 and you can then get the gun from his house. With this gun you'll be able to take out the Wallcrawling enemies easily.
Again the game is easy but it is time consuming. The hardest part will be mustering the effort to finish the game three times and collecting all trading cards. Good luck!