Dogs are trainable. It's a fact. Even the most seemingly stubborn and headstrong dogs can learn and train. Despite following instructions religiously, there are a wealth of small mistakes we might be unknowingly making that are in fact hindering rather than helping our progress.
Missing the exact moment your dog is performing the behaviour you want to reinforce leads to you unknowingly encourage the wrong behaviours entirely. If you're too late, or even too early, you've missed the opportunity to praise what you're trying to teach, and confusing your dog in the process. Fix it: When training, watch your dog closely and only mark at the exact moment your dog performs what it is you're looking to encourage. For example for a Sit: mark and reward as soon as their bum touches the floor!
Ignoring good behaviour It's easy to get swept up in the "bad" behaviour, getting frustrated or even telling your dog off when they're misbehaving. But have you ever given them praise or a reward when they're doing the right thing of their own accord? Fix it: If, for example, you're looking to stop your dog jumping up, instead of giving them attention only to tell them to stop while they're doing it, make sure to shower them with praise whenever they're calm, relaxing, sitting or standing nearby you. After all, they're doing exactly what it is you want by not jumping up, so let them know! Just saying NO Stop that! Get down! No! Come here! Go away! Get out of there! Go in there! Put that down! The list goes on and on. Imagine you walk into a shop and reach for something you need. The shop owner shouts "DON'T TOUCH THAT!". What do you do next? Does that mean you can't be in the shop at all? Are you allowed a different one of the same item, or not allowed that item at all? Are you allowed to get other items on your shopping list? The simple "No" you were told leaves you with an infinite list of questions regarding what it is you're not allowed to do and what it is you are allowed to do. Though you mean something very specific (stop jumping up me, stop eating that plant, stop barking at strangers) "No" is an extremely broad signal to your dog and your message is entirely lost in translation. Fix it: If your dog is doing something you don't want them to, give them something else they are allowed to do instead. If they've stolen your slippers, instead of engaging in the wild goose chase (which, by the way, is an enormous part of the fun for your dog), offer them an alternative that they are allowed to chew on and play with instead, and put your slippers in a safe place they can't get to.
The wrong mindset
This applies to you both. If your dog is overexcited and unfocused, they aren't in the right space for learning. Equally, if you've had a bad day, are feeling irritated or impatient, you are not in the right space for teaching.
Fix it: Train your dog when you are both feeling relaxed and in the right frame of mind to enjoy the process together. Let your dog calm down from any excitement, make sure they're toileted, not too hungry or too full, and make sure you're feeling relaxed and positive before starting any training. Frustration If you want your dog to be calm, you have to be calm. It's easy to feel impatient and want to see results NOW, but rushing your training, skipping steps or failing to properly follow the process through in full depth won't get you your results, and simply shouting your new command at your dog louder (& louder...!) won't make them understand it any faster.
Fix it: If you find yourself getting riled up or frustrated at your progress, stop, take a break and take a breath. Remember that these things don't happen instantly - we don't go to school aged 4 and come out the next week with a degree - and that it's a learning curve to be enjoyed together, not battled against.
Failing to prepare Is preparation to fail. Trying to squeeze in a session 10 minutes before bed, before the guests arrive, or before you head out is not the right time. When the TV's on, there's a party next door, or in the middle of a busy park is not the right environment.
Fix it: Make sure you have enough rewards (be that food or their favourite toys), enough time, a quiet, calm environment, a relaxed, focussed dog and a positive mindset before any training session you undertake. If you don't have a clear idea of what you want to achieve or exactly what steps you need to take to get there, you aren't setting your dog up for success. Make sure you prepare for each session with a clear goal in mind and the right tools to get there.