High altitude: only subjected to geostrophic deflection force and horizontal pressure gradient force.
Low altitude: subjected to geostrophic deflection force, horizontal pressure gradient force and friction force.
Direction: The horizontal pressure gradient force points from high pressure to low pressure. The geostrophic deflection force is right in the northern hemisphere and left in the southern hemisphere, perpendicular to the wind direction.
The direction of friction is opposite to the wind.
The wind direction at high altitude is parallel to the isobar.
First find out the low pressure and high pressure, then draw the horizontal pressure gradient force, and then draw the wind direction (within 90 degrees) according to the geostrophic deflection force.