GamerSpeak:

Tips for Crackdown Orb Hunters

We recently asked the Xbox.com forum community for their best tips on finding all 500 agility orbs and 300 hidden orbs in Crackdown™. Here's a sample of what they had to say. To read all of the responses, check out the forum.

Turn up the sound! Sometimes, you land so that it's right behind you, and if you don't hear it, you might just move on by accident!
Corrin Avatan

Looking at NIGHT really helps out and I'd recommend traveling the streets on foot while looking up to find those low ones not visible from the Rooftops.
Night Raider

If you have a surround sound system and you hear the orb sound, turn your character around a little at a time to pinpoint the exact direction.
Dmbledore

Never assume you found all the orbs in a certain portion of the city. Sometimes orbs respawn at different areas if not found for long enough, so they may respawn at a spot you already found an orb at. Also look in out-of-the-way areas such as the top of buildings or in a rock structure. Orbs tend to be hiding in places that most civilians or gang members can't reach.
Trochan

My favorite thing to do right now to look for orbs on the lower levels is to jump on top of a civilian car and let them drive you around so you can just look for the orbs and not worry about running straight and looking also.
Dark Jedi Kain

If you've defeated all the bosses, go back to where they were. I found maybe 5 or 6 just by going back to the boss in The Volk where the fat lady in spandex is (sorry for the mental images).
SMG owns the BR

Once you get past about 480 orbs, make sure to have a friend play co-op with you to help you find some of the hard ones and most importantly to talk to (I'm serious). You could go insane while looking for those little green things.
Rokossovsky

Definitley don't just skip the orbs that you see, thinking you'll save them for later because you want to go beat a boss or something. Make sure you grab those orbs when you see them. If you are trying to look for orbs only, turn off crime after beating the game.
ChriSquared

Check the shores and rocks, there not just limited to buildings.
PaNfOoT

Separate the map into areas, and then thoroughly search each are until you are positive there are no orbs left.
Deadly Cyclone

Take a ride on street level and look around the mundane, lower sections of the Earth. They aren't always up in the highest buildings, sometimes the ones you miss are the ones you've jumped over.
Banstyle

What worked for me best was getting onto the top of a tall building and using the scope on the sniper rifle to scan the city … I found quite a few doing this!
OzFalcon

I also created an Excel document with number 1 to 300 for the Hidden Orbs and 1 to 500 for the Agility Orbs, with columns of 50, so it would all fit on one page. I printed the pages out and cross off each number as I confirm each one according to the map that I use. There are several maps floating around out there, so whichever one you decide to use for your search, stick with that and then go back to the spots where there might be duplicate orbs and see if you missed any along the way.
GHOSTGUNDAM

For hidden orbs check near: Bosses, caves, rocks, bridges, staircases on top of buildings that SEEM to go to nowhere, hard to reach places, on top of those little domes on top of buildings, doors, and near the agency tower.
GhostRider655

Run the rooftop races. The route may be one you don't usually take and you may find a few you missed. If the race times out, simply start over and keep looking.
Khu

Check all of the rocky coasts and mountains, especially in Volk and also believe it or not, it;s easy to miss agility orbs on low billboards in some parts of Los Muertos as I found out.
K4rn4ge

Do NOT play with a partner because they will distract you and be like, "Hey, do you have this one?" Then you go there, and it's not there, and you forget where you were searching before that.
UniteTomorrow

The Agility Orbs on rooftops come in sections. If you see one agility orb, check the row of rooftops nearby, there will likely be more orbs in the area.
SkidzKyle1224

I found that crouching helped me in getting some that were on beams … I tended to walk off the beams, but crouching is a more precise movement.
Sgt Bruster

Swim around the islands. I must have found 50 or 60 orbs along shorelines, bridges and waterways. 
HUUS

Turn on Small Speaker Mode: This greatly amplifies the sounds the Orbs make.
Motosan

If you find yourself in a position that you MUST abandon, and you are carrying limpet mines, deploy one but DO NOT detonate it. You can later use the pinging sound of the limpet mine to help guide you back to the area where you first saw the orb. 
CeptionLYL