That is why you should do plenty of theory exercises. So you can learn how to write notes. There is no easy way around it you just have to do it. It takes lots of practice and is very much analogous to how primary school children start writing letters and numbers.
Your theory teacher should give you good guidance to keep the notation neat and then it take lots of practice.
A few tips.
The treble clef.
It starts on the middle line on the staff. Goes from twelve on the clock with the clock all the way round. It then makes a little twirl back to twelve. It goes straight down from twelve to six and makes a little twirl to the left.
The Bass clef.
This one starts on the second line from the top on the staff. You write a little dot and then it curls to right. You then you write to little dots above and below in the spaces from the second line from top.
Notes that have stems go a certain way. I always tell my students note stems go like the letters "p" and "d" not like "b" and "q" The stems are also note just lines that go up from the middle of the note head.
Traditions regarding whether notes stems go up or down as follows. If the note is notated above the middle line of the staff the note stem goes down. If the note is notated below the middle line of the staff the stem goes up.
If the note is notated on the middle line the stem will do what the notes before the note that is on the middle line did. So if the note before the note on the middle line is above the middle line and has a stem going down the note on the middle line will also go down.
Notes take one space whether they are on lines or in spaces. If a note is one a line it takes half the space above the line and also half the space below the line. If they take all the space above and below the line they are too fat and incorrect.
If notes are in space they simply take all the space between the two lines. Again if they go over or below the lines they are too fat and incorrect.