Overview:

-Estimated achievement difficulty: 4/10
-Offline: 37 (690)
-Online: 10 (310)
-Approximate amount of time to 1000: 10-15 hours
-Minimum number of playthroughs needed: 2
-Number of missable achievements: 8
-Glitched achievements: No
-Do cheat codes disable achievements? No
-Does difficulty affect achievements?: No

Introduction:
Welcome to Lord of the Rings: Conquest. There is a total of 47 achievements worth a total of 1000. It requires a minimum of two playthroughs. One playthrough is the single player "War of the Ring" Campaign, also known as the "Good" campaign. The other playthrough is the "Rise of Sauron" campaign, also known as the "Evil" campaign.

You will unlock 17 achievements worth a total of 400 by simply playing through both campaigns, and that's just playing each level, you are more than likely to get more. The remaining 600 will consist of getting kills with certain classes in campaign or local multiplayer and getting kills online as well, and also assorted online achievements but we'll get to that later.
I have not heard of any glitches disabling you from unlocking achievements, as I did not come across any.

There are 8 missable achievements in the game and 6 of them consist of killing heroes with heroes, whenever you come across a "boss" and are given the option of becoming a hero press for yes. If you die, you will have to die a couple more times, to be given the option to become one again. The other 2 missable achievements require you to kill 300 hobbits in the last level of the "Rise of Sauron" campaign, the Shire. They will respawn, so just keep killing them without destroying the buidings. The last missable achievement requires you to die by a fell beast or eagle. Just do the Osgiliath level and when you get to the bridge, stay there and you will get picked up by a Nazgul.

Step #1: "War of the Ring" Campaign
This is the first campaign, in order to unlock the "Rise of Sauron" campaign, you must first complete this. I would do this on the easiest difficulty "Casual" since there are no achievements if you beat it on higher difficulites. After each level you complete, you will recieve an achievement. Make your way through the campaign, not really trying to get other achievements, when you get to the Osgiliath level, get the achievements when you have to get so many kills with certain classes with certain abilities and the one when you have to get killed by a fell beast or eagle, just go to the bridge. At this point in the game you should have about 12 achievements, give or take a few. Progress your way through the campaign untill you get to the end.

Step #2: "Rise of Sauron" Campaign
Just like the other campaign, I advise you do it on "Casual," instead of playing the good, you'll play as the the evil this time. Progress through the campaign, one level at a time, and try to remember to play as heroes at "boss" battles by pressing . At the last level, Shire, you'll have to kill 300 hobbits in one playthrough, they respawn so it shouldn't be a problem, just don't destroy the buildings. When you beat both campaigns, you should have around 33 achievements, more than halfway done.

Step #3: Online
Now that you have beaten both campaigns, it's time for some online gameplay, online isn't dead yet, and it's still pretty active, you shouldn't have a problem finding a match. There are 10 ranked online achievements with a total of 310. The first online achievements I recommend doing are the kills and go from there, they can be boosted, almost everyone playing online is boosting, or done the old fashioned way. If you decide you want to do it the old fashioned way, you will want to join a match with very few players.

Once you have done those, there are only a few achievements left. Do the 4 "big" ranked online achievements next, the 50 ones, they tend to be the hardest.
1.Requires you to get the most points in a ranked match, I reccomend doing Conquest, and just capture points, instead of going for kills.
2.You will have to capture 10 points in a Conquest match, again, probably easiest boosted, find a friend and get the ranked online ones.
3.You will have to capture a ring with Frodo, must be done on the level Shire and you must be a hero, capture 2 rings, you then will have the option to play as Frodo, capture the last one as Frodo.
4.You must capture 3 rings in a a ranked Capture the Ring match, you will get this the same time as the above one.

Step #4: Mop Up
In this step, you just have to get any achievements you have left remaining, if any. One you may have left is the co-op one, simply complete a level in co-op. Two others you might have left to do are the achievements to get 20 kills with Legolas and Gimli. They do not have to be done ranked, they can be done local, just do a game of Hero Team Deathmatch and play the level Mount Doom so you can play as Legolas and Gimli, and change the options to 100 kills. If you have any remaining achievements, get them done. At this point you should have a total of 47 achievements worth a total of 1000

Conclusion:
To wrap this up, Lord of the Rings: Conquest is a fairly easy fun 1000, and most players should be able to attain all 47 achievements. The list is pretty straight forward. If you are still missing any achievements, here is the link to the guide: Lord of the Rings: Conquest Achievement Guide

[x360a would like to thank Coadster1 for this road map]