Also, a trainer will be able to provide equipment to practice on - which means that you don't have to buy or make it yourself. Look for a trainer that uses reward-based training methods and avoids choke chains, which can catch on the obstacles and cause your dog serious injury.
Bear in mind that dogs have to be over the age of 18 months before they can start training in agility - this is to prevent your dog damaging his joints. You shouldn't compete in agility if your dog has arthritis or hip dysplasia.
Although the obstacles vary, the more often-seen ones are:
Weave poles. These are between six to twelve poles that are put in a row. The dog has to weave in between each pole as quickly as he can. Most dogs love this obstacle and become amazingly fast.'
Seesaws, otherwise known as teeter-totters. These are just like the ones that children play with. Both ends of the seesaw are painted a different color to the plank - these colored parts are known as 'contact points'. Not touching the contact point is a fault.
Hurdles. The hurdles in an agility competition are like the ones that horses jump over. Two hurdles are often set out next to each other, so the handler has to direct the dog which one to jump over.
Tyres. These are suspended in windows in rectangular frames - the frames are sometimes painted to look like wells. The dog has to jump through the tyre.
Tunnels. There are several variations of this obstacle - some tunnels have openings that are made out of fabric, others have two entrances.
A-Frames. These are named because of their shape, which is exactly like a capital 'A'. The dog has to run up the side of the A-frame, and come down the other side. This obstacle has contact points.
Tables. The dog has to jump onto a table, lie down and pause for around five seconds before moving onto the rest of the course. Jumping off before the judge's signal is a fault.