It is very difficult for any singer, especially experienced ones, not to be occupied with his/her voice type. For beginners though voice types become clearer through regular exercise of the voice paired with healthy vocal technique. To get a general feel for your voice type three things need to mostly be taken into consideration: Analysing range, tessitura, and timbre.
Range is basically the lowest and highest note you can sing. Obviously, higher voice types tend to sing higher, and lower voice types tend to sing lower. In general, these upper and lower limits can give clues about your voice type. (Main singing/speaking voice is to be used when looking for range. Falsetto and whistle tones should not be included)
How do I figure out my range? Sing through your range with a piano or another instrument and record the highest and lowest note you can sing. Be careful not to strain yourself - ranges are most useful when they only encompass notes you can hit healthily and consistently.
Tessitura is a concept worth specific mention. While most singers will have significant overlap in their range, the tessitura, or comfortable singing range, is very useful in determining voice type.
How do I figure out my tessitura? One relatively easy way to determine tessitura is to sing a simple melody, such as the first couple of lines of a familiar song like "Happy Birthday". Sing the passage in a variety of different keys, and record the keys that feel most comfortable and sound most resonant for your voice.
Timbre is essentially the "tone colour" of the sound. Almost every acoustic sound is actually made up of a combination of different sounds called overtones. These combinations cause our brains to perceive different sound qualities, which we can describe with adjectives like "bright", "full", "clean", "brassy", etc. Each voice has a unique timbre, but some general timbre characteristics tend to be associated with certain voice types.
How do I figure out my timbre? Timbre is a subjective and often ambiguous concept, so it's very difficult to define without professional help.
All the above mentioned are broad guidelines that will give the singer a general idea of his/her voice type. To further understand your voice type it would be prudent to seek professional guidance from a voice teacher.