Campagin Scoring

this may help.
http://halo.wikia.com/wiki/Campaign_Scoring
and this
http://www.bungie.net/News/content.aspx?type=topnews&cid=12828

 

well i have all campaign scoring achievements (even orpheus, which was a pain to get)
but what i would suggest doing is signing in a guest, and letting him just sit there like a spawn point and moving him up everytime you reach a checkpoint, it's cheap, but it works. i did not use this method but i did it on my second time round and it worked.

 

Campaign scoring is one of the easiest part of the Halo3 Achievments.

Put the Difficulty on Normal and turn on these skulls -

Skull Name | Multiplier | Effect
Tough Luck - 1.5x - Enemys dodge grenade throws
Catch - 1.5x - Enemies throw a lot of grenades. They will always drop 2 grenades when they die
Fog - 1.5x - No motion tracker. What's so hard about that.
Famine - 2x - Dropped weapons have half the ammo or energy.
Thunderstorm - 1.5x - All the enemies are one rank higher than usual Example
Mythic - 2x - Enemies have double health

All those multipliers make it really easy.

Edit - I had all the silver skulls [except blind of course] when I was doing it just for fun also, though they don't add multipliers

 

well of course you would need some skulls, the difficulty can be heroic or legendary for best results.

 

No, there's absolutely no need for Heroic or Legendary. I got all of them first try on Normal. Here's what I did, and may help you:
-Play with another friend over Xbox Live, let him get kills too, if he wants, but if you see on the Scoring that you are getting too far behind, tell him to let you get some kills. The only level i reccomend he gives you a lot of kills on is Cortana, and maybe some parts of The Ark
-Put at least the underlined skulls on: Tough Luck ( throwing one more grenade wont cost you a thing), Catch (watch out for them grunt nades), Fog (you really wont need you radar, trust me on this), Famine, Thunderstorm, IWHBYD and G-B day party (silver, but g b-day party always cheers you up )
-Every level has a different time multiplier bonus.
Try finishing it usually in less than 15 min. to get 3x multipliers. 15-20 min = 2.5 x multiplier, 20-25 min = 2x multiplier. Those are usually it. If not, they are proportionally correct. Check your ticker on the bottom-right corner of your screen to see the current time multiplier. This only multiplies in the end, so let's say you ended up with 7 500 points on Cortana, with a 2x multiplier when you finished on your ticker. You will get a total of 15 000, being exactly what you needed for that level.

Honestly hopes this helps you. Took me a while to write

 

it can actually be harder on normal because of the amount of skulls you have to turn on, if you can i recommend heroic, but i managed it on legendary.

 

all the skulls i cited though are pretty easy, and do not change gameplay that much in campaign. Radars: Who need's em in campaign??? you always know where you're enemy is, unlike matchmaking.
And heroic or legendary are completely unnecesary (in my opinion)

 

I can get through a lot of the levels with normal (skulls: thunderstorm, famine, catch, tough luck, and iron if you have a second controller [be very careful, it sucks to die at the end]).

On some levels (mainly flood levels) you can get through with heroic no problem. I can solo a lot of legendary missions by myself but the multiplier sucks so I wouldn't recommend it.

The only level you should have a partner (or second controller) is Cortana. Those flood pop out of everywhere.

 

i had to do cortana with a friend, and i made him sit back for pretty much the entire level, only once we had gotten out of the reactor/big round room did i let him come into the action, it worked perfectly though.