I force myself to do things.... Give myself an hour and say, right the there is clock, do something with that (waves instrument/program in the air) now go! And don't stop.
I find just finishing something difficult, so don't worry about it, a lot of stuff you come up with will never go past the "oh I think this is crap" phase anyway, accept that, but don't let it rule you. Just save after an hour and bam, you got yourself a couple of minutes of noise, then come back to it a week or so later, give yourself another hour to work on more...
There are a lot of ways to beat 'writers block' but the most effective is usually just sit and write, don't be afraid of not living up to your own standards and always come back to something later (days, weeks even months) if there is something that excites you.
My couple of quid there,,,
I personally loathe going back to older stuff, rarely ever do I actually come up with anything I like from stuff I got stuck on before. YMMV
I use Logic, so for fun sometimes I'll mess around with some of the loops, there are way too many to choose from, but I'll find one that sounds rad. I'll change the pitch, try to re-create it with other instruments, add shit, subtract shit, try to flesh it out a bit, that usually gets the juices flowing.
i never really get "writer's block" because i never feel the compulsion to write something without also having pretty specific ideas of what to write. if i'm working on something, it's because i already have ideas. if i don't have any ideas, then i can go weeks without writing something and feel totally fine about it.
it seems like some people feel this compulsion like "i have to write something NOW" even when they have no ideas. that feeling seems weird to me and i cant really relate to it. what so wrong with just not writing anything for a while?
Pretty much all my "songs" are unfinished, I mostly use Nanoloop so I just come up with lots of small ideas and musical phrases and then jam on them live, hence my lack of full releases. Anyway if other people or I like some of those ideas I'll flesh them out to full songs. I don't do that a whole lot but at least it gives me a huge library of material to play live. I find I tend to write the most material when I'm coming up to a deadline 
So basically my method for overcoming writer's block is writing (and saving!) lots of small song ideas, no matter how small, and have a reason & timeframe for everything to prevent procrastination and messing around too much (for example: i am writing this song, which is a floor destroying dance track, for my live show this saturday, and i will achieve this by ...). It's also worth coming to terms with the fact you won't like everything you write, you will have off days. Take some time out, no point in dragging out your misery ... unless you have to finish your project soon, in which case inspiration will come, trust me 
i never really get "writer's block" because i never feel the compulsion to write something without also having pretty specific ideas of what to write. if i'm working on something, it's because i already have ideas. if i don't have any ideas, then i can go weeks without writing something and feel totally fine about it.
it seems like some people feel this compulsion like "i have to write something NOW" even when they have no ideas. that feeling seems weird to me and i cant really relate to it. what so wrong with just not writing anything for a while?
zis, with ze exception zat you can generate ideas very easily by letting your fingers take over, whether on an instrument or on a pc keyboard fulla crumbz. no need to let ideas occur to you when you can remind yourself what ideas sound like just through plain unconscious play.
doing improviation with friends helps me a lot. Even if it isnt with chipstuff, you come up with some neat ideas.
I know a few ways, many were already mentioned.
There is an article (can't find link) that suggests developing a standard form to your music (in conventional song that's verse-chorus-verse-chorus-bridge but need only be exposition-development-ending in instrumentals,) that you can resort to when you're stuck; though I've done this it leaves me feeling that all my music does the same thing.
Hitori Tori (search in YouTube for some godlike performances) suggests taking several of your unfinished clips and using them as fragments in a larger work.
The ugliest of my personal writer's blocks lasted four years and did not end until I had decided that traditionally professional music was not for me, and then I started talking to people just like the ones reading this forum, and remembered why I thought I wanted to make music for a living in the first place.
You can get through any creative block if you can remember why you wanted to compose music in the first place. I got around mine when I remembered what made making music fun.
Leave your PC recording in the background while you're making music. (Don't feel self-concious, nobody is going to hear these) If you come up with nothing that day listen back to the recording. Chances are you'll find something good in it (like a riff or something) which you'd forgotten about, then you've got something to start with the next day.
noodling on other instruments, effects, and attempting covers usually motivate me to write a song i like.
also avoiding the forums helps me a lot.
hell yeah.
also, i try and cover a song from a genre that i feel i don't fit into, and try and recreate the sounds from that on my platform. Often I'll find that one of those sounds is interesting enough to try and use in an original piece.
A writers block in one of my areas of creative output generally seems to mean a boost in another. For the days you don't get things done at all, even though you want to, my recommendation (if you have the time and patience to spare) is to stay off the net, put the tracker in full screen and keep at it until you get something good out of it. You might feel bad about it along the way, but once you're into what you're doing it's bliss, and you'll probably find yourself having too many ideas.
As for sources of inspiration, for me they can be everything from strong emotions and bad/good days to purely technical stuff like a different tool or sound chip, or by coming up with melodies on an instrument I don't usually play (or haven't picked up in some time). I'm pretty much stuck doing the same thing all the time on keyboards, but I have a guitar and an electric bass that end up with a different tunings pretty much every week.
This happens to me every so often but it never lasts long. I usually just take a break completely from creating anything and spend more time going outside, praying, reading, etc. Just generally changing my surroundings helps a lot. It's a cycle.
I know that my creativity (i guess), and productivity in a given area kind of goes in cycles. Like I'll have a few months where I'm all about visual art, whether it be live visual type stuff, graphics, or whatever, and then I'll have a few months where I'm all about music and trying to make songs.
So I guess the advice that could come out of this would be to try and find another creative outlet during your musical dry spell. It doesn't need to produce anything wonderful, but I know I get frustrated with myself when I'm not producing anything.
when i get this way (as i do frequently) I spend less time writing and more time playing with sound with out care of notes. sound design can inspire songs sometimes. if you dont worry about notes and think of texture it can come out with some interesting stuff. thats how most if not all of my songs start.
Pretty much all my "songs" are unfinished)
this is a very wise attitude. nuff said. i don't think any pollock painting was ever finished. the mona lisa is unfinished. fuck that painting though... i guess some ppl like it.
switch your medium - all musicians could benefit from trying something that is not sound based. most have tried at some point. switching the medium makes you think differently - opens up different areas of the brian. try another consol - or another artistic outlet completely. try some pixel art maybe. get away from judging your own work - in my opinion that's what makes artists want to slit their wrists. try some meditation - clear your mind. i dunno. thats some hippie shit - but those bitches, although way too extreme, did touch on some ideas that were decent.