One of the things that we often have to understand in order for our equanimity to grow is to recognize the Three Characteristics of Existence. So learning how to do internal and external reflections can be very helpful to bring this understanding of the Five Reflections that we teach into our life, especially the fifth one, balancing our Compassion with Equanimity. One of the short forms of this is, "Many things are beyond my power to control". By reminding myself of this helps me to have more equanimity in my life, especially with meeting the negative four of the eight worldly dhammas.
Bringing more awareness of impermanence into our life, by using these special mindfulness activity reflections that we teach throughout our life, is also helpful with growing in Equanimity. If we start to see impermanence more in our life, then we will begin to accept it more. If we see that impermanent things are not really mine, then we will come to accept it more in our life. If we learn how to develop more understanding of the Characteristics of Existence, especially that Dukkha does exist, it will help us accept them more in our life. These three characteristics: impermanence, Dukkha and the impersonal nature of things, by learning how to see them and accept them more clearly in our normal life will help our equanimity to grow.
In our relationships to others, understanding the Four Noble Truths helps. Remembering what the Four Noble Truths are: Dukkha exists, and the true cause of it, and that each of us is responsible for walking the path out of it. In that way, when we are trying to change somebody else, it is good to remember how difficult it is to change ourselves, and that it is not within our power to change somebody else; we can only change ourselves. By reminding ourselves of this is helpful.
One of the meditations that I encourage people to do in order to get more understanding of this in their formal practice, so that they can bring it more into their life, is learning how to bring people to mind, have compassion for them, and then do the equanimity reflection, "They are the owner of their own Kamma". Realizing that if they are suffering, and it's something within themselves that is the cause of it, then they are responsible for the ending of it. too - it's not within our power to change that. Just as if something within our own mind is causing our suffering, it's our responsibility to try to end that. So understanding what belongs to who basically is going to help your level of equanimity to grow; learning to accept that Dukkha does exist, the true cause of Dukkha, what it is, and that each of us are responsible for ending it within ourselves.
If we remember the Four Noble Truths more in our normal life it will help to bring more Right View, which helps to bring more equanimity. Because without understanding Dukkha with its true cause, it's very difficult to have equanimity towards it because we expect that it shouldn't be there, or we expect that we have the power to end it in everybody, or we expect that we have the power to prevent it coming.