The good thing about inspiration is its spontaneity – it may come down at you at the most unexpected moment letting creativity boost and pour out some chef-d'oeuvres. But at the same time spontaneity is its bad feature too – it may leave just as suddenly as it had visited you. That’s okay if writing music is one of your minor hobbies and those splashes of creative energy are just a means of getting you distracted for a while. But if music plays a more substantial role in your life and even comprises a part of your life-earning sources, it would not be superfluous to learn to manage the ways you are inspired for work. Hopefully, some of the inspiration channels described below will be the right for you to find the Muse when she’s so needed.
It is not always necessary to go too far in search of things to inspire you. As Frederick Delius used to say, “Music is an outburst of the soul”. It is first of our vision of the world so why not delve in your own life experiences. We all store moments that affected us greatly at some point – memories of interesting people, exciting trips, controversial disputes, random meetings and what not – that’s a perfect ground for cultivating your enthusiasm for music writing. You could express musically your opinion towards these personal experiences. Or use them for defining the direction for further work. Or simply recall the emotions that used to be stirred when living these moments and get them afloat.
Another great composer, Igor Stravinsky, was convincing us that “Lesser artists borrow, greater artists steal”. Let’s make use of it too and try to turn our mind at other music works. Go back to your favorite compositions, albums, bands, musicians and name what you love about them most and what it is about their music that gives you an example to follow. It doesn’t mean you should steal others’ ideas or style, but people whose creative work we respect make our inner selves aspire to create something no less wonderful and worthwhile.
No matter where you live, we are all bound up with Mother Nature and it can help us regain strengths and provide an additional charge. Especially if you are ‘a child of concrete jungles’, try to take a longer walk in the park or better get out of town to enjoy a wilder spot. You don’t need to be a romantic nature to find sheer pleasure in sunsets, for example – there are no equal sundowns anywhere in the world so your experience is sure to be unique every time. Even better if there is a contact zoo nearby – communication with animals can be a very sincere and invigorating experience. No zoo, no parks, no wild nature? No problem. There are lot of amazing HQ photographs that can be inspiring as well. Surf the net for outstanding nature photographers, or visit some world panorama sites or have a look at the online webcams to watch, say, an eagle’s nest in the real time. Anything may work! 
The biggest masterpieces are usually reflected in more than one form of art. Thus, where there is an awesome book, there are movies based on it, where there are great paintings, there are beautiful poems dedicated to them and so on. Why not use other form of art, let’s say poetry, as a source of your inspiration too? Reading the lines of an impressive poem you can have your inner voice prompt you some ideas of wrapping the verses in a music cover. Same about any other work of art that has influence on you. All you need is to concentrate on your associations and impressions triggered by it.
It goes without saying that inspiration is a very individual thing and there is no universal recipe for causing it. But even if you are not feeling inspired at the moment do not leave your work for later – rather keep trying to find your own secret means of getting encouraged and the Muse will no doubt will be back. Good luck!