Can you keep a habit for a week? How about two weeks? Can you do something for a whole month? If you can't yet, work up to it and start with positive journaling. Keep a journal that you can easily refer to every day, and write down three things you are thankful for – things that give you happiness and make you an optimist. Then, write down one happy moment that occurred that day no matter how big or small, impactful or not - just get it in there.
Alternatively, each day write down one positive thing you are grateful for, ideally for at least 3 months. This has two effects: 1) it forces you to review each day in a positive light. 2) you begin to approach each day trying to find something positive in it. The cumulative effect is that your perspective becomes rooted to one of optimism and gratitude. You can read it when you're down.
Changing your perspective is a great start. For example, overly apologetic people have a habit of latching on their faults. Make these changes and see the positive difference.
Sorry for waiting on me = Thank you for waiting up for me
Sorry for talking your ear off = The conversation was enjoyable, thanks for hearing me out
Another great start is to look for something that can take your mind off things that you do not enjoy. Finding hobbies to burn your excess energy is a positive and keeping yourself from being too idle results in a healthier outlook on yourself and life.
Positivity is not some inherent part of our nature that we can't change, develop or put on. It is malleable. It is something we need to cultivate. To exercise, like a muscle. It is a way to approach ourselves, and the world. It doesn't have to affect our natural optimism or pessimism. Optimism or pessimism is going to decide whether you think your next diet is going to work or not. Positivity is you choosing to go on this diet, and sticking with it.
Learning to rest, not to quit.
Setbacks happen and plans change suddenly, while things go awry. This is the way of the world. When something takes you off track, it's important that you get back to it. It is never too late.
Self-Compassion for Our Flaws.
Imagine if you talked to your friends the way you talk to yourself. Now imagine how you talk to your friends when they're down on themselves. That's the kind of compassion you deserve, and you deserve to give it to yourself. Write down a personal flaw you have. Write down a previous failure of some kind. Now, use your imagination and imagine a friend of yours came up to you and told you these things. What would you say to lift them up? What would you say to comfort and console them? What would you tell them about getting back on the horse, rising when we fall, and doing your best and letting the chips fall where they may?