I decided to post all of the steps and rules for catching shinies using the pokeradar here so that you don't have to look through the video everytime you forget some thing!
Things you will need:
- Pokerader
- Pokeballs
- Lots of Max repels
- A high level pokemon with strong, high PP moves that can knock out pokemon in one hit.
- a Pokemon that can weaken the shiny so you can catch it. This is optional, but usful if you're not "Swimming in Master Balls".
- PP restoring items such as ether and leppa berry. (If you are low on Leppa Berries, I suggest planting a bunch of them first)
Now that we know what we need, let's get started!
An optional start is to find Dawn/Lucas' Sister and find out where the pokemon are swarming that day. (It is said that swarming pokemon are a lot easier to chain than the normal ones)
Next, find an ideal patch of grass. An ideal area is a field of grass that almost completly covers the screen.
Use your Max Repel now. This will keep other pokemon away while you use/recharge the pokeradar.
Finally, use the Pokeradar. It will save you the time if you set it to Y/Select ECT.
Chances are, you'll see four patches of grass shaking. start with a patch that isn't glittery.
If you choose the right one(assuming you're going for a swarm pokemon), the swarm pokemon will appear. if not, just keep trying until you do find it.
Once you run into your target pokemon, faint or catch it. This will begin the chain. DO NOT RUN FROM THE POKEMON!! This will break your chain.
After you defeat your first pokemon, notice that many other patches of grass shook. after your initial faint/catch, it's important to keep a few things in mind...
RULES OF CHAINING:
Rule #1: If you don't see four patches shaking, it won't break your chain to enter one, however it is reccomended that there be four. Don't worry if you can't see them all, I have bad eyesite myself. =p
Rule #2: after your first patch, all other patches must shake the same way. This means no glitters if you didn't happen to start with a glittery patch.
Rule #3: Never choose a patch of grass that will force you out of the Radars range; The radars range is the area on the screen that you can see the shaking grass on. consider this if you only see 2 or 3 patches shaking. this is because there may be other patches shaking off the edge of the screen.
Rule #4: ONLY choose the patch farthest from you. Make sure it is at LEAST four patches away.
Rule #5: When you need to use a repel again, you must reset the radar. choosing a patch of grass after using a repel will break your chain.
Rule #6: Never choose a patch of grass that is on the corner/outside edge of the grass. Also beware of objects jutting out into the grass. (Fences, trees, ect.)
Rule #7: Don't choose a patch of grass if it is right beside another moving patch.
Rule #8: When in doubt, reset the radar and try again.
Rule #9: as stated above, never run from a pokemon, and never let it flee if possible.
Rule #10: Never use your bike.
and finally,
Rule #11: If you see a patch of grass that sparkles twice dramaically and seems to have a different colored hue, it's a shiny pokemon. proceed there with caution.
It's a lot to remember, but in time it will become second nature.
One more thing to go over before moving on; Reseting the radar.
the radar will recharge after every 50 steps. If you come across some patches of grass that aren't ideal for you, reset the radar. the Max Repel will protect you against un wanted wild pokemon that may break your chain during this process. If you can't remember where each patch of grass was, take a chance on a direction and move in those two squares until the radar is fully recharged.
once you use the radar again, it will reset the patches of grass without breaking your chain! Remember, be extreamly caution; don't just rush into the first patch of grass that seems okay. if you have any doubts at all, reset the radar; you'll be doing this a lot.
WELL, THAT'S ALL THE BASICS!!
All there is left to do now, is tell you a few tips and tricks!
#1: Swarming Pokemon tend to make better chains
#2: Never enter the grass above your character unless you can see all four patches of grass wiggling! It will be hard to see it there, so be careful when moving that way. Remember, four is the maximum amout of patches that will wiggle, so if you can only see three or less, do not move up!
#3: If you don't have a ton of Master Balls, it's good to have a pokemon that knows Super Fang or False Swipe in your team. This will make pokemon easier to catch. Any immobilizing statuses like Sleep or Paralisis are ideal as well.
#4: If you're chaining pokemon that know Self-destruct, whirlwind, Roar, ECT., you might want to have a master ball around as a last resort. It's pretty annoying when you finally find the shiny and then it blows itself up!
#5: If you're hunting an electric pokemon, put a pokemon with the special ability 'Static' at the front of your party. it is said that this will make you more likly to run into your target pokemon.
#6: Poketch app #20 is very helpful; it will help you keep track of your current chain.
#7: Put your Max Repels at the top of your item list to save time; remember that repels are in the item pocket, not medicine! I sometimes forget that. >.>
#8: At some point stop chaining and reset. some say that 40 is a safe number to stop chaining at, but 20 can work if you don't have the patience for that; It depends on how willing you are to raise your chances.
#9: If ever you need a break, take one! Just make sure you will know where you are when you come back. It's best to take breaks in the middle of a battle or right before you reset the pokeradar. But whatever works for you, works for you. Real-time will have no effect on your chain, so take all the breaks you need.
Just remember to plug you DS into the recharger if you need to leave it on for awile, and putting it in sleep mode won't hurt either.
#10: Keep in mind that if you save your game, turn it off, then come back, IT WILL BREAK YOUR CHAIN.
And that's all I can tell you!! Stick at it, and you too should notice results.
(Credits to Shuko for the tutorial, and to Buster The Fox for adding some helpful comments/posting it in words! Also, if re-used, give credit where credit is due!)
So now you can have even more fun chaining pokemon.

Use this list to help memorize all of the rules and tips, or if you happen to be on a computer that dosn't have flash player, or whatever else the case may be.