(this bit is for the song you posted 2 posts above mine) pretty much the whole string part is off in different ways at different places, some places the timing is weird, some places the notes are very out of key sounding, maybe they just clash with the lead, but they sound out of key or very sharp, the string part right before that little rising scale bell/harp thing you threw in there is very off time, almost sounds like 2 songs are playing at the same time.
my advise to you for now would be to start a new song, stick to a major scale. and just use 2 instrument channels, both piano, do one as the right hand (right half of the piano/lead) and do the other as the left hand (left half/rhythm) and try to write a song with just the piano to keep it simple.
work on a few things, timing, song structure, sticking with the scale, using simple major chords, 5ths and 3rds (look at my example pic for reference).
now a couple things to keep in mind that dont sound good.
1) lets say your left is playing a major chord with C, E, G. you dont want the lead playing a D or an F because then its gonna sound like youre just mashing the keyboard with your fist. playing 2 notes right next to each other simultaneously sounds bad. if you play c+d together is sounds bad, but c+e sounds good.
for example at what im trying to tell you do do here, lets say your left hand is playing some 3rds c+e >d+f > e+g > f+a, if you played on the right to accompany it d > e > f > g, it would sound like shit, but if you played f > g > a > c it would sound alright. it would be very simple and plain but for example sake i kept it that way. just try keeping all your note within 3rds and 5ths of eachother for now to get a grasp of it
2)stick with the timing. you dot want to try starting stuff a odd places in a progression.
take for instance you have your left hand doing a basic rhythm, with a chord at each quarter section of the grid, you dont want to start lead parts at odd intervals at say, 2 or 4 (if you look at the grid, you have 4x4 squares like |---|---|---|--- | is a bold line, - is a fine line, you dont want to start a note in the lead at the #2 or 4 of the fine lines, you want to start notes at 1 or 3.)
personally i will do some of the things i say not to do, but i do them on purpose to do syncopated parts(
http://en.wikipedia.org/wiki/Syncopation), make some songs have a creepy sound (off key, or 2nd notes)
its kinda hard to explain with just typing but hopefully you understood that, if not ill get you a screenshot of what im talking about.
just start simple and get a grasp for timing and note placement and move on from there
