The adorable Oli, who has gone to his FurEver home.
Time: You can volunteer your time to help out at a shelter. Shelter dogs get very lonely, the more people to walk and play with them, the happier they will be. You can also try and raise awareness of issues like responsible pet ownership, desexing and puppy farms.
Donation: While money always helps rescue organisations, donating things like blankets and dog food can always help too. Ask your local shelter. If a friend has a pet that they say they cannot afford to desex offer to pay for it. Especially with wandering male animals such as dogs and cats, they could create multiple litters of kittens and puppies that could be put down.
Adoption: If you know you can take care of a dog for life then consider taking in one or two to give them a loving forever home. Please only consider this if you are willing to take care of them for the rest of their lives.
Fostering: Another way you can help out is taking in shelter dogs as a foster carer. This means you will take care of the dog until it finds a forever home. Shelters are often overcrowded, taking in a foster animal means you might save it from being put down, or that you might help an anxious and stressed animal recover so that it can be rehomed. If you really fall in love with it you could always adopt it too.
Talk to friends and family about responsible pet ownership, adopting from shelters instead of petshops and desexing pets. If someone you know talks about getting someone a pet as a present remind them that pets are a lifetime responsibility. They need to make sure that family is able to keep the pet and will not just get rid of it when it is too much trouble or not so cute anymore. Remind them that adopting from a shelter saves lives, while animals in petshops can come from puppy farms. Even if they do not, a puppy from a petshop is much more likely to find a happy forever home than an older dog at a shelter, even though they deserve love just as much. And of course, desexing pets means there will be less unwanted animals out there who may be put down.
If you know anyone who rents out their home encourage them to allow pets on the lease, rental agencies often just don't allow pets because of possible damage but the renter would have to pay these damages anyway. More pet friendly rental properties means more people who can take in foster animals or pets from shelters.
Adopt a senior pet: Old pets are harder to rehome, some people don't want to deal with an animal who may have missing teeth, arthritis or die within a couple of years. But they still have so much love to give, and deserve to grow old with love.
Lobby for reform of animal rights, ending puppy farms, etc.
If you can think of any more ideas, comment! :)