A guitar-specific way is to use Guitar Pro. In the program, you can write tablature (or even click on the frets you want) and the program automatically turns them into standard notes.
The layout is pretty simple:
You type the fret number on the bottom line, and the respective note appears on the clef:
And this is the fretboard that you can click on:
Besides that, a way to learn the notation is, probably the most common way, by reading (and singing) solfege.