When ever I come up with a melody, it somehow always sound to.. like childish. Pop and R&B are hot on the market now these days... and I'm aiming for that. Could you please give me some advice???
Sorry to take so long getting back to you. Actually something I learned at the recent CMN conference reminded me of your question and helped me think how to answer it.
There are basically two elements to a melody: its rhythm and its intervals. If either the rhythm or the intervals (or both) in your melody are too simplistic, the song may come off sounding "childish."
Let's look at intervals first. An interval is how far up or down the pitch moves between two notes. What I learned at the conference was that small children learn to sing certain intervals first. My guess is that songs for very small children use mostly intervals that small children can handle, so melodies using mostly those intervals may sound childish because we are used to hearing them in songs for small children. Another way of looking at it: since our brains learn those intervals first, one could argue that they are the simplest intervals, and songs based on those intervals may sound simplistic.
OK, so what are those intervals and how do you avoid over-using them?
What I learned at the conference was that the interval from ME to SOL is the first one small children can sing. Then they add LA. On a piano keyboard you can hear these intervals by playing E then G then A. Play G G E A G E - does that sound familiar? "A tisket a tasket" or "Nanny nanny boo boo" or "It's raining it's pouring, the old man is snoring." All these follow the same pattern, and it sounds pretty childish.
Expanding on this idea, the major chords are made of simple intervals - thirds and fourths, so perhaps a melody that stays within the major I, III, and IV chords is in danger of sounding childish or simplistic as well. If you don't know what I'm talking about, don't panic. I barely know what I'm talking about myself. This is all music theory. I recommend that you take any chance you get to learn as much music theory as you can, and your writing will become more sophisticated for it.
But as a quick fix, just to get your creativity going, try this. Write a melody using only the black keys on the piano. That will get you playing with some intervals that are more sophisticated, or at least different from those you might be used to.
Look this up on the Internet: pentatonic blues scales. Once you learn a few of those you'll start to incorporate some really cool jazzy intervals into your writing.
Now on to rhythm.
Again, a simplistic rhythm could make your song sound childish. The simplest rhythm would be a line of quarter notes, or a steady beat. "Where is thumbkin, where is thumbkin?" Add in a couple of half notes and you get the Barney song (also known as "This Old Man" to us old-timers): "I love you, you love me, we're a happy family." The rhythm is: quarter quarter half, quarter quarter half, quarter quarter quarter quarter quarter quarter quarter. Yawn.
Again, this is more music theory. But you don't have to know what a quarter note is in order to hear that the rhythm to the Barney song is very simplistic. So how do you spice it up? How do you keep your rhythm interesting and sophisticated? Make it swing, use syncopation, use rests. Vary it up a bit.
First take a look at your lyrics. If the words of the song form a long regular rhythm, then try re-writing it so that you break it up a bit. For example:
"I baked a juicy peach and apple pie, and then I had to shoe away a fly."
It would be really hard to write an interesting or catchy melody for words that follow such a long regular rhythm. Give it a try.
Now try this:
"Hey, fly! Get offa my pie!"
Similar idea but I boiled it down to a few key words. This line has a natural rhythm to it too, but it's a bit more varied and interesting. Try writing a melody for it. Which do you like better?
"Juicy juicy apple pie. Get away, fly! Get away, fly!"
My point is that if your lyric is stuck in a rut, do a little brainstorming and you'll be able to find a bunch of different ways to vary up the rhythm and make it more interesting, and therefore more sophisticated and less childish.
Finally, some general advice: Listen, listen, listen. Now that I've drawn your attention to intervals and rhythms, go listen to some pop and R&B or whatever you want to write, and pay attention to the way the pitches and rhythms move around. Try to pick up on some new ideas that you can add to your own writing.
Have fun, and I hope this helps!