Always review the complete molecule using the reference screen before making any moves.
Next, study the play field and plan your moves. Remember, once a piece is moved it may not be possible to return it into the starting position.
Think through your every move and try to visualize the trajectory piece will follow once a directional arrow is clicked.
When using the keyboard to move pieces make sure that the desired piece is selected. If a wrong atom is marked as selected, use the Tab key to switch between the pieces until you reach a desired one.