Grow your confidence
Believing you can is really the panacea for anything you might want to do in a dream, thus it deserves its own section in this guide.
The basis of this section is, dreams are heavily influenced by your thought and emotion, because all is taking place in the same mind. So, by learning to control your emotion, stay and think positive, it will be much, much easier to keep the dream under control and make it steer in the desired direction.
Imagination is the real power in dreams: trying to lift a heavy object by brute force will rarely take you anywhere, as you are losing focus and imagining there will be some resistance, like the weight, that keeps the object down. Instead, imagining of having superpowers, or the object being weightless, will work much better. Seeing yourself succeeding before attempting will almost result in a even higher rate of success.
What I’m trying to say is, how can brute (and fictional) strength take you anywhere in a world completely made of fantasy? Dreams are the realm of the mind, and thus it must be the mind to accomplish feats, not the body (not even the dream body, as it is a representation to you of the real one). Next time you must do something, relax your body, and use your imagination instead: by visualizing how the process will be, you are already putting it into (dream) reality, as the mind is actively working towards the visualization. Get engaged with your senses, with your emotion, make it feel as real as possible for you, and it will actually become real, as you actually are in the realm of your imagination. (I really can’t stress it enough)
Chances of success can be boosted up a tremendous amount by starting with something more familiar to you, or in which you already have put confidence. It can range from a jetpack to fly for the tech lovers, to a potion made from a friend you trust, to dancing side by side with the best dancer you know. Just invoke the aid for something or someone that you think it will make things easier, and it will. After that, you are free to continue using the aid or realizing it was you all along and acknowledging it as your own power.
Tips
- Always, always remember to take it easy. Getting mad at things will bring you absolutely nowhere. Take some deep breaths instead, think positive, and think of an alternate way of doing the task at hand: it won’t be long before you think of another one 
- If you still find difficulties, then get some help! It can come by any mean, from dream guides of any sort (already described in the long-term solutions), to instruments with magical properties, either single-use or not, to anything you feel it might help really. And go forward little by little: do something that feels easy for you first, then grow in boldness, and reach for the stars, and beyond them! As long as you think it is possible, it will be indeed.