Puppy training is so important, it is the first stage of life which is so key to learning for puppies. Puppies have fast developmental periods, each associated with behavioural and physiological changes. The big stage is socialisation and starts as early as 3 weeks and begins shortly after the senses are functional. Although this process is usually restricted to a limited time period (when the puppy can easily learn from positive and negative experiences), it will impact their future life as an adult dog and their relationships with their owners.It can last only up to 16 weeks, this is why it is good to start training your puppy as early as possible. If your puppy hasn’t had their vaccinations you’ll need your vets permission or it is best to start with carrying your puppy and seeing new things from in your arms or in a stroller for short sessions and just take in the world slowly and reward them for doing so, even better if they’re reacting fairly calm.
Everyday things can be scary if a puppy has never seen them before. 
During the critical socialisation period, they can learn to accept things around them as part of their normal life
with nothing to worry about. It is therefore essential to expose a puppy to as many different
situations and individuals as possible during this period in a positive way, as after this period,
the puppy may find it more difficult to cope with unknown situations. This is all new for a puppy, even the things we might not think are that scary ourselves, such as a plane in the sky, bikes, trucks, high-vis jacket, stranger in a hat etc. will all be strange if a puppy hasn’t experienced this before, but seeing it from far away and from a young age, positively and followed by a treat will help your puppy learn that this isn’t a threat. Your pup can gain confidence and doing this can help prevent future fears from developing. This socialisation stage is where their brain has developed to a point where the puppy can fully take in and respond to environmental stimuli. The socialisation period is a challenging period for puppies as many changes occur. So it is best to carry out short training sessions, and keep adventures short and sweet. A young dog must not be overwhelmed throughout this period, as both an under-socialised puppy and/or one that becomes highly stressed during its first encounters May ever new experiences and is more likely to develop stress-related behavioural problems in later life. These include general nervousness, noise phobias, separation anxiety and fear aggression. 
A successful socialisation process will help puppies develop into happy, well-balanced adult
dogs and to prevent the development of future issues. Puppy socialisation and training classes are more and more popular and recognised as beneficial. Many owners are unaware of normal dog attitudes and how to interact with their dog. Puppy classes help owners better understand how to live with their puppies and give them the opportunity to socialise with other puppies, dogs and people. Puppy socialisation classes are often designed for puppies between 8-16 weeks of age, but of course there are training classes for puppies and dogs of whatever age to be able to attend. Puppy classes, when properly carried out, can be very helpful, as correct Puppy Training raining while the puppy is in the more ‘receptive’ socialisation phase, dramatically increases the likelihood that the dog they grow into will stay in its new home for life. However, it is also vital that steps are taken to ensure these early experiences are ‘positive’ and that the puppy is able to cope appropriately with each new stimulus.
The classes can be a fun and effective way to encourage your puppy to learn and develop into a confident, outgoing dog in all circumstances. They can increase the likelihood of a harmonious owner-dog relationship, help provide useful training techniques, get puppies used to strange different places, noises and smells, train inhibitions and self-control, get used to other dogs being nearby without the need to react or approach. They can also help prevent the development of issues such as mouthing, eliminating in unacceptable places or chewing, as well as providing useful tips and advice for puppy parents. 
The 3-9 month stage is juvenile phase and this is where your puppy will increasingly explore their environment and their behaviour responses refine. From 12 weeks they’ll go through maturation, although their learning will continue but their stable relationships with form with other family members.
Environmental enrichment should be provided to each puppy (and adult dog later) to ensure their welfare when living in domestic conditions. Enriching the environment is also a very important treatment tool for many behavioural issues. It can be easily accomplished by provided to every single puppy some toys for playing, kongs/food puzzles/ toys to use for distraction and self-soothing, appropriate chew items, safe and comfortable resting areas and comfy bedding, physical (walking, jogging) and mental exercise (positive reinforcement, floor food mooching, searching for ball/food/hiding items, training), food-enrichment by using food-dispensing toys, sensory enrichment, auditory: music (reggae), human voice; human interaction with petting, grooming, fun such as playing and exposure to outdoor smells and time to investigate.
Reward good behaviour that you want to see more of, DO NOT punish bad behaviour. Try to think about redirecting or distracting your puppy into something you want to see or do instead of stopping or punishing unwanted behaviour. Be patient and consistent and try to start from day one or early, right after adoption. Reward your pup when they respond well to new situations and never punish them – this will prevent fears in the future.
Exposure to loud noises, staying home alone and having to meet with unknown people or animals (through their normal training) are amongst the most stressful situations for puppies.
Most of the situations puppies (and adult dogs later) find difficult to cope with are related to fear and stress. In many cases, puppies have not been properly exposed to or prepared to deal with such situations during their early age (when their brain is more receptive).
When afraid, a puppy will display a “stress response”, which is a general physiological and
neurological response of the body to adapt to a threatening situation. Which can lead to the following signs in puppies or dogs: Urination/defecation (diarrhea), Increased motor activity, Vocalisations (crying, whining, barking), Salivation, Trembling, Panting, Looking away/Avoidance, Nose-liking, Yawning, Low posture.
Consider using a CD-based or downloadable programs – such as Sounds Scary* can help the puppy get gradually used to loud noises. It is best to start these when they are young, but also play extremely quiet at first and very gradually increase the volume, keep sessions of playing the recordings short and try to play these when your pup is calm and in a relaxed state to begin with. Also, avoid trying to train used to the loud noises in fireworks season or around a time with loud noises, as the idea of gradually increasing the exposure to the sounds and increasing the volume can go out the window if a loud firework goes off.