That is what helps me, looking at nodes and drawing it out from there. If you just put dots on a straight line as signify them as nodes, then you can just do a wave like motion through the nodes and it should come out as expected.
For example lets say you have 4 nodes. Put 2 dots on either end of the line then the remaining 2 dots equally in the middle. From the 1st to 2nd dot, you go above the line. 2nd to 3rd dot will be below the line. Then 3rd dot to 4th dot will be above the line in a wave-like shape.
