When you have a practiced mind, you will be a very selective sifter of your own thoughts. You will not miss a single opportunity that comes through the cracks to feel thankful for and in our meditative practice, what better ways than to pick our breath to do it? When you gather all of your focus and concentration and direct it to breathing in a manner where the rhythm and timing of it soothes you, it will gradually get easier to be still and not find yourself (your mind) wandering about carelessly.
You will be "in tuned", "aligned" and "in harmony" with your breath and as you practice daily consistently, you will start to enjoy that quality time set aside just to concentrate on your breath. It is the best way to start off having something to focus on to quiet the mind and using the breath is effective because it makes audible noises (but not overbearing) and you have complete control over it to exaggerate the way you breathe to the degree it holds your attention for periods long enough to stay focused throughout your practice.
Therefore, deliberate breathing equates to deliberate thinking. You pay attention to it on purpose and then proceed to use it as a tool to serve you directly and intentionally. You see instant results. The more focused and concentrated you are, the less you feel distracted or the need to fidget physically while you are "meditating". Meditation comes in many different forms and ways. Some verbally chant sutra and play music that will guide them through that 20-30 minutes, some find other forms of outlets to ensure that quality time was set aside to focus on themselves. As long as it takes your attention for at least a full 20-30 minutes without interruption and allow you to focus on you, that is meditating.
You have to keep in mind, each practice does not need to be categorized into a "good" or "bad" attempt. Your own practice is for the sole purpose of completely honoring and loving yourself therefore, you can't evaluate it as you would do a performance. If you carry this mindset of "grading" yourself with you, it will entirely write off the actual purposeful intention of it and if there's any goal to these practices, it is very simply - to learn. It is the quickest route to mastery and growth when you take a "learning mind" with you.
If the time goes by and you forget or miss your practices, just "forgive" and "restart" again. That is the very first step towards accepting yourself. Each time you feel like you fall below your own bars and standards you've set, don't beat yourself up and wallow in self-pity and just acknowledge your small efforts and baby steps you have taken. It matters how you approach the subject because the way you handle forgiveness to-wards yourself is the way you would apply to others around you, even if you don't know it just yet.
You'll be imperfect at this, but that's okay. Investigate what have thrown you off course, learn from it, then in that space of self-awareness, you create a new opportunity to "invite" yourself to begin again. "Letting yourself in" is the first big step you take in learning to have full acceptance of your freedom to make mistakes and understanding they are not flaws, but rather, personal attempts to try something new. You will eventually get the hang of it if your heart was set on mastering it - whatever it may be.