The problem with the best songs is that they sound as though they took no effort to write.The kicker is that it's occasionally true.

Certainly, if a melody sounds belaboured, too cleverly crafted or too complex, it's automatically disqualified from the 'good' category.
Not that simplicity is any de facto indicator of quality, let alone originality. When you really only have twelve notes to work with (five of which need to be used very sparingly), your chances of repeating a significant chunk of someone else's work are surprisingly high. The bulls-eye is a melody and harmonic structure so simple it seems anyone could think of it, everyone feels affinity toward it – yet no one has created it until today.
Pondering such ideas brings me closer to believing that songs are not so much written but discovered; a songwriter simply picks a song out of the ether and polishes it down to its true essence. The best songwriters are most keenly attuned to the school of songs swimming in the psychic sea around us.
As legend has it, the song “Yesterday” came to Paul McCartney in a dream; he spent minutes after waking firming up the details and lyrics of the piece, but weeks trying to ascertain whether he hadn't inadvertently heard someone else's piece and simply re-played it in his dream.
There you are, Sir Paul – one complete, classic pop-song, fully-formed and presented gift-wrapped in a dream. I suspect even J.S. Bach would be jealous of composition so effortless.
Such a smooth, inspired process avoids that awkward first pitfall of songwriting: the feast/famine stage.
If someone is writing out of obligation – feeling they must come up with a song today – they'll usually suffer the Famine. Ordering your imagination to come up with a specified idea seems to be an excellent way to make it freeze solid and inert, or produce only cliches. Alternatively, if you're sitting around with a musical instrument and letting the ideas flow freely, unbound by expectations, the Feast overwhelms. Trying to piece together a song from the myriad ideas, variations and potential directions is sometimes the proverbial herding of cats. Which melodic idea is the best? Which will ultimately connect best with other ideas to form a song? When should one stop generating ideas and start marshaling them into some semblance of a song? You can only take your best guess, or be overwhelmed by the choices. Lately, I've been more inclined to pick the ideas that simply intrigue me the most, practicality be damned. If it's fresh to my ears at such an early stage, it stands a better chance of not outstaying its welcome after many hours on the workbench.
The next stage is sometimes the closest thing to musical drudgery – forming the ideas into a structure. While this process can be hugely inspiring to complete, I suspect it demands a lot of my mental processing power. I have literally fallen asleep on more than one occasion programming the drum machine for the initial demo or strumming chord after chord, running through scenarios until I find one I like. Sometimes this is like locating one last ingredient for the mortar, sometimes it's filling in all the mortar and a few bricks, and sometimes it might as well be building the whole frigging wall...perhaps repeatedly.
From this point on, things tend to get quite fun. Arrangement ideas, choosing tones, recording instrumental and vocal parts onto the demo – here the ideas are welcome to flow freely, but the existing structure keeps the choices from getting too overwhelming in number and diversity. By now, the basic song has probably developed enough personality to be enjoyable to play and explore. The beauty and curse of playing in a three-piece band like MLB is that I can't get too carried away with arrangements – no keyboards, one backing vocal part, and very economic use of the guitar. The wall of power chords is not an option (and it's usually not to my taste anyway). Still, virtually everybody cheats at this stage – including me. Sure, my band only has one guitarist, but nobody has ever complained that the 'studio' version of any given song has a layer of acoustic guitar under the electrics, or that there seems to be an extra backing vocalist (whose voice sound's suspiciously like mine) on the track. Hey, if you like a more 'authentic' recorded version, buy our live album. I'll keep you posted on the release date.
There are certainly songwriters who have an easier time of it than this, or a harder, more trial-and-error experience, or just different. Chances are, if the songwriter has been at it for many years, he or she will have gone through different stages; sometimes it's easy, sometimes it ain't, and occasionally it seems impossible. In the latter instance, I find it best ('though still difficult, after many years) to deliberately write garbage. To paraphrase a suggestion of Natalie Goldberg in 'Writing Down the Bones', set out to write the worst crap you can. Does it work? Well, let me put it this way: sometimes you meet your objective, and often you don't...so how can you lose?
As for songs you might typically hear at a Mike Luno Band performance, the pedigree varies widely. The lyrics to 'Get Inside', for example, poured out like a faucet, and in fact I ended up with a couple of extra, unused verses; but hammering the thing into a coherent, structured song took several attempts over many weeks. 'Row Boat' just spilled out of me one afternoon when I was stumped halfway through 'Villains Anonymous'. 'Heart Beat Up' was quick and easy (inspired by a 2-bar phrase in Stravinsky's 'Rite of Spring'); 'Free Fall' took quite a few false starts before I found my footing. 'Pretty Good Joke', 'Turn' and 'Caesar's Palace' originated from jamming with Curtis, which is usually a fun and inspiring process; and 'Mistress Mona' (and to a lesser degree, 'Rugburn') was an attempt to write silly crap...which the band, live audiences and I ended up really liking. The operation was a failure but we saved the patient. Although my memory is sketchy regarding the specific genesis of most of my other tunes, they tended to be mid-difficulty – great moments of inspiration mixed with grim determination and spells of near-hopelessness. I suppose if it were all a walk through the woods, it wouldn't be such a kick to reach the end of the process, hear the playback and think: hot damn, this actually turned out better than I'd hoped! Somehow, moments like that keep me going back for more, even if my songwriting income couldn't yet buy a decent used car. Most songwriters I know are in the same boat – and like me, they wouldn't consider trading back the time spent for an instant. Like any other gambling – sometimes it's easy – and that pays for all.