Hello,
I have been playing piano, strictly playing, since the age of 6. Since that time, many wonderful melodies have entered into my mind. I finally want to learn how to notate these on score.

So I started to do this, but many problems came up.

How could I identify a time signature? Rests and all that to satisfy time, cut time or a faster tempo, noting accidentals, etc, etc... It's a lot different to play from the score than to transfer music to paper.

Where should I start out? I want to write music on paper, but I want to get it right to, so that people who find it can also play what I've intended them to, and not what my mistakes show. Please point me to some books, some advice, or some good websites.

Thank you so much.

:-/

The general process to what you're describing is called 'dicte' (or transcribing). The art of transfering what you hear (in your head, outside, or other) onto paper.

First of all you should be aware of music theory, and all the tiny details. There are several websites out there that will aid you to that. Then you should also be aware of harmony. Since a note can be G# or Ab, you will always have 2 choices on how to spell a note (if you leave out the double accidentals). This may lead to problems if you decide to spell C major as C-Fb-G or other.

Knowing these will help you but not get you there.

You should start practicing your ear. To be able to spot the notes. Then rhythms. How does a 3/4 differ from a 4/4. How is a 6/8 different than a 3/4 and so on. It's on the beats, on the feeling, on the 'pulse' of the work. How are more complicated rhythms like (7/8, 9/4, etc).

In order to find the right time signature you should play the work (your work) and find the repeated patterns in there. It, most probably, get repeated every 4 beats, or 2 beats or 2 beats or something. Then you will need to try the metronome on yourself to see where you stand, or compare it with other works you already know. Accidentals you need to know which scale you're at (music theory helps here), and after that you will also need to know if you're in a minor scale or a major (or other). Accidentals generally apply like this: If they are part of a chord (for example a 7th in a chord) then the spelling goes by default. If you move upwards melodically you usually use sharps, and in the opposite situation you use flats.

Some ideas to get you staring.

a. Ask your teacher to help you (train you) in transcribing music by ear).
b. Find excersizes to that around the web (google it).
c. If you have a midi keyboard plug it on your computer, get some free (or very cheap) software and get recording. THEN check the score and see what you played. If you have a metronome at the same time it might help a lot (to keep the tempo steady, etC).
d. Finally, make your score, make the recording and show it to us. I'm sure that apart from me, other people will chime in and help out in noting what feels right or wrong.

(Note all the above pretty much apply to tonal music, right? :))

It may help to try out your ideas, using a notation program.
There are some free ones available.
Or you could download the free demo of this one:
http://www.noteworthysoftware.com/

You will be able to experiment to your heart's content, and the software will play back the notes you input.