You've spilled coffee on your shirt, you're heading to another day at a job you don't love, and you're starting to think you don't have what it takes to succeed. Almost everyone has days like that. For some, it's an occasional occurrence, but for others, it's a constant part of their everyday existence, but regardless of where you fall on that spectrum, it's possible to change that negative inner dialogue and boost your self confidence. It may even be easier than you think. Here's five simple things that can help.

1. Practice gratitude.

The benefits of gratitude are plentiful. Research and anecdotal knowledge agree that gratitude improves physical health, enhances empathy, reduces aggression and affects physiological health in positive ways. As if that list weren't impressive enough, gratitude also improves self esteem.

Practicing gratitude isn't hard, and it takes mere moments. At the end of the day when you crawl into bed or in the morning when you first wake up, think of three things you are grateful for and write them down or say them to yourself. It doesn't matter what you express gratitude for -- running water, a new sweater, your favorite relative or best friend, your dog, the shine of a newly washed floor are all great ideas.

Even if you struggle to think of three things the first few times you practice this exercise, as time goes on, practicing gratitude becomes easier and easier, and ultimately, you may find that sticking to just three items becomes the real challenge as you tend to notice more and more things for which you feel grateful every single day.

2. Stand tall.

Good posture is often associated with confidence, but it doesn't have to be an effect of confidence. Rather, it can also be a precursor to confidence. Studies indicate great posture can boost energy levels, decrease stress levels, lower fears, increase positive emotions and most importantly increase self confidence. Unfortunately, retraining your body to have good posture can be challenging. Luckily, however, yoga can help.

Yoga works on aligning your core, and even just a few sun salutations every morning can improve your posture throughout the day. Essentially, those few minutes of yoga remind your body how great it feels in perfect alignment. As a result, throughout the day, you will notice yourself engaging your core, throwing your shoulders back and straightening your body.

To make standing tall simple, consider taking a yoga class or following a yoga video on a regular basis. Additionally, do a few poses in the morning and a few before bed. If you spend a lot of time on a laptop, an assembly line or anywhere else where your body is in a slumped, crouched or non-straight position on a regular basis, a few poses throughout the day can also work wonders.

3. Focus on small goals.

Sometimes, the size of the goal can be the biggest hurdle when it comes to self improvement. Set yourself up to succeed with small goals. For example, if you want to create a daily yoga practice, start slow with a few poses before your shower or a class on Sunday. Don't commit to jogging three miles to the yoga studio and taking an hour and a half hot yoga class every morning before work.

Eventually, you may achieve a goal like that, but it isn't reasonable to go from nothing to that within a day. Work your way slowly up to your goal by setting and meeting small goals. As you check off each goal, enjoy the sense of satisfaction and boosted self confidence you receive from accomplishing your goals.

4. Create routines that are pleasing to you.

Boosting your self confidence shouldn't feel like a chore. While it's important to set goals, improve your posture and practice gratitude, it's also important to enjoy yourself. The more truly pleasurable things you do, the better you feel and ultimately, the better you will feel about yourself.

Do you love to sip a cup of coffee with cream and stare out the window or watch the morning news? Does listening to a certain song in the morning while you get dressed put a smile on your face? Then, make those things part of your morning routine. Even if you have to wake up a bit earlier or send your kids to school on the bus instead of driving them, the benefits of engaging in positive routines will ultimately be worth it.

Alternatively, you may love making a bowl of popcorn and watching your favorite show once a week -- give yourself permission to do that and make it a date. These routines don't have to be complicated or long lasting. They just have to be pleasurable.

5. Whisper a positive mantra to yourself.

A mantra is a simple phrase that you create and repeat to yourself. Ultimately, just as yoga has your body retrain its posture, a positive mantra can help retrain your brain into positive thoughts. Create a mantra that has the power to boost your confidence. For example, use the phrase, "I am a light to everyone I meet" or "I am a strong beautiful person" or even just "I love myself." Repeat this phrase in the shower, during your commute, while you're waiting in line at the grocery store or during other downtimes in your day.

Self confidence is critical. It changes how you feel about yourself and ultimately how you look at the world. Boosting your self confidence can open new opportunities, improve your relationships and open the door to more success on every level.