Find a melody by one of your favorite composers and change it up a little. Do themes and variations, etc. to practice working with a tune and creating your own melodies.

Instead of trying to find the melody, let the melody find you.

Thats something they can't teach! Personnaly I think simple melodies are as good or better than complex. Melody owes more to rhytmic variation than pitches( in my humble opinion). Oh and never harmonise a melody before you've finished it-you'll run out of steam....I think thats what the guy before me was saying......

There are loads of ways....First, establish the key. Then copy another rhythm of a melody you like (an example with audio is available at www.how-to-write-music.com/Pincharhythm.htm)
All you have to do then is use the same rhythm and change the notes to fit in with the piece.

Things to consider:

1. Tempo of the melody and piece. Obviously needs to be slower if a more melancholy tune, or faster for a more happy tune.

2. Key

3. Repetition. You need a certain amount of repetition for it to become catchy, but not too much so that it becomes boring.

Hope that helps.

Not much more I can think of. Melody owes more to rhytmic variation than pitch. Don`t be too critical of your work, you`ll improve your chances of creating a good tune by simply increasing your output. Also ( might sound obvious) make sure there are no distractions around you.I find it useful to scriibble a few random notes on the page so that I`m not just staring at a blank sheet....can be daunting! Hope that helps!

Every melody starts with the first note. For a given backing, the first note and its sound can set the tone for the melody (or the first few bars, say). If you don't already have a melodic idea for a piece, try various starting notes for the melody, with different sounds if you can, and pick one that takes the feeling of the music where you want it to go. Try it a few times and look for the next note that works. Repeat until a tune starts to appear. Once you have a few notes, the melodic idea should start to gel, and you should be able to play around with it from then on.

One thing: every time you add a note, review the piece at normal speed. This sort of feeling your way through a tune can be quite slow, and you can lose track of the pace of the melody. In other words, take care not to write a 'slow tune' that sounds wrong at the intended speed of the piece. Unless the slow tune works, in which case, slowing down the piece might be the better plan - the tempo could be the very thing that's holding you back from finding a melody!

i've been writing original melodies for years now.
you have to hear melody(not the melody just the sound you want) in your head first, it dosen't have to be clear, but you need an idia of the style and sound of the music you want to creat befor anything els. the more music you listen to the more ideas will come to you.

when you've found the type you want to write, find some songs of that style and look for patterns and forms...that you can go off of. (for exaple a clasic standard hym has a -four messure vers,repeat four mesure verse with a cahnged end, four or five mesure chours, repeat las vers- form) those patterns will help organize your thoughts.

then you find your melody with that sound in your head. brain storm and plug things into that pattern and style till you find the perfect thing. from there you can write harmony, possibly go off that pattern, find the write sounding key, do whatever els after you've found your melody

for starters, I'd say start simple. simple is key not only for beginners but for perfecting a catchy tune as wel. you can later develop this into a more complex melody once you are comfortable with your grounding.