i wouldnt say landscapes are easier on the long run but its a more intuitive and easy way to start with traditional painting imo. there is alot information out there how to draw the planes of a face. just google "planes of face" and you have a good start. andrew loomis has a good approach specially if you fancy heroic characters. you can google his books easily - they are accessible for free.
if your goal is to achieve some kind of realism it is more about learning how light and shadow cooperate with each other and color theory. after all you can only create the illusion of depth so its kind of logical that you understand how we percieve the light reflecting on objects ( or the lack of light ) so you can artificially re-create these events.
for example an easy way to create depth in landscapes is with the use of aerial perspective. if you look this up on wikipedia the first introduction already gives you all information you need to re-create that effect :
Aerial perspective or atmospheric perspective refers to the effect the atmosphere has on the appearance of an object as it is viewed from a distance. As the distance between an object and a viewer increases, the contrast between the object and its background decreases, and the contrast of any markings or details within the object also decreases. The colours of the object also become less saturated and shift towards the background color, which is usually blue, but under some conditions may be some other color (for example, at sunrise or sunset distant colors may shift towards red).
so - if something is further away we will have lighter colors which fade to a neutral light grey/ white ( or background color ). the next thing is how light bounces of off objects. how the surface "swallows" a part of the spectrum of the light lets take plants as example and you can look up the following information :
Green plants are green because they contain a pigment called chlorophyll. Chlorophyll absorbs certain wavelengths of light within the visible light spectrum. As shown in detail in the absorption spectra, chlorophyll absorbs light in the red (long wavelength) and the blue (short wavelength) regions of the visible light spectrum. Green light is not absorbed but reflected, making the plant appear green.
if the surface is hard and sleek the light hitting the object doesnt scatter alot and you will get a small but intense highlight compared to a rough surface. if you would zoom into a rough/ matte surface you would see cliffs and gaps ( like a frottee towel ) hence light gets reflected in much different ancles so naturally you dont get a tiny intense highlight but a feathered out illumination instead.
light hitting an object will always bounce off and hue ( color ) may change during this process and eventually hit another object close by.
so the more you know about the science of light and how stuff actually works the easier it will be for you to create the illusion of things existing without existing