Manage your dog’s experience around agility equipment so the only things they rehearse are the things you want them to get good at. Here are some tips:
1) Try to manage your dog’s time on course so that they are doing ONLY 1 of 3 things:
They are actively working for you, they are actively being rewarded by you, or you have your hand in their collar. Your instructor will not be offended if you take the time to collect your dog before turning your attention to their observations / feedback / instructions. Having foundation skills of FETCH, COME, ORIENT TO MY SIDE, TUG, STAY are key to being able to ensure only one of these three things are happening.
2) Try to ONLY practice high energy and focused work. Get organized before your training session. Have your aides, bars, equipment already set up before you get your dog. Have your thoughts together about what you are wanting to do. Set up your the level of difficulty of your challenge so your dog has a high probability of earning a high rate of reinforcement. Keep your training session short and take lots of breaks. While your dog is on break - put them back in their crate so they can absorb what they just experienced.
3) If your dog can’t handle the distractions or freedom (off leash) of the environment, and is prone to go visiting, sniffing, wandering - don’t allow that to happen - keep them on leash or a ribbon until they have earned more freedom with their attention and focus (see also tips on how to help your dog get into a working mindset). But also ask yourself, if what your dog is telling you is that they need to work on attention/focus rather than what you want to work on.
4) Build as many behaviors as you can away from agility and the equipment so that by the time you get onto the agility field, your dog is already proficient with the foundation and basics. For example, teach a really great stay behavior away from equipment, in the living room, back yard, skateboard park, supermarket entry way etc.... so that when you get in front of a jump, you are much farther along with a solid behavior and your dog is more likely to rehearse good work on the agility field.
5) Practice your skills away from the agility field and your dog. Just like your dog, practice your handling footwork, your timing and placement of rewards (such as throwing a toy accurately) away from equipment and your dog. You don’t need a dog to practice your front cross footwork (remember “can of spam”) and if you do practice, then when you get out on the field with your dog, you can focus on helping them to only rehearse a nice snappy response to something you are already good at.
6) A great foundation enables your dog to rehearse a great mindset on course in all respects. Teaching your dog how to choose self control helps them stay in the zone for learning. Teaching your dog how to choose you over other interesting things in the environment helps them focus on what you are doing with them. Teaching your dog what your invitation to play sounds like enables them to learn with keen and happy confidence. Teaching your dog how to offer behaviors enables you to build independent performance right from the start. Teaching them to work for play builds a habit of energetic and persistent effort. Etc. etc. etc.