When thinking about lyrics in terms of rhyme type, it is not necessary to rhyme words directly (Hat, cat, bat, mat, sat etc). Other rhyme types can be used to give a more interesting sound, flow and context to what is being talked about in the song. It is important to add, that sometimes you don't need to rhyme at all. If it works and you like it, go for it. Rhyme usually has a direct link to the syllables in the words and the similarities of each syllable in a word, to another word. Below are the different kind of rhyme types and some corresponding words.
Perfect: test, west, best, nest.
Half: this is usually when the end of the words are the same but the beginning may be different. Tall - Tell, Farther - Winter, Bank - Think.
Far/False: This is typically when part of the middle of the word has a relationship. Patience - Station. Testing - Jester, Black - Flap.
Below are a simplification of some of the more common rhyme types used, though there are many other ways of paring words outside of this. It can also be subject to the delivery of the words in the song, as to whether words work or not. Sometimes something just doesn't sound right. Other times it can flow perfectly and can be a good tool for defeating expectation. We naturally expect words to rhyme perfectly.
AABB ABAB AAAB ABBA
Often referred to as space and space in terms of vocal application. This is the idea of leaving space in the delivery or phrasing of the lyrics/vocal, to allow the listener to take in what is said and help the song flow nicely from one part to the next. It is typical to sing a line and allow the music to go round for a couple of bars or so, before coming in with the next line.
A normal approach to this idea would be to apply a busier approach to the vocal application in the verse and leave more space in the chorus. A chorus tends to have a more sustained vocal, but then again, the rules are there to be broken and this all depends on what you like and what you feel works for the song.
The key is choosing when to leave space and when to use a more frequent vocal application. Often combinations of both help to keep the listener interested and help to break up each part of the song.
PERSPECTIVE, STORY & LYRICAL APPROACH:
What is the song about? A song can be about anything, but if you start with a blank canvas, it can be hard to know where to start or it can be hard to get off the starting blocks. It is better therefore to slim down from the start what the song is about.
A good place to start is bywhat inspires you at the time you choose to write a song, or what's on your mind in general in the context of your life. Grab a pen and paper and do some brainstorming.
Start with your initial idea and write anything you feel relates to it. Try not to let the critic in you rule, otherwise you may not write anything down. The more you write, the more you have to draw from.
It is often best to draw from your own life experience, as it is more than likely, others have felt or do feel the same way as you. At least if it is a personal experience, it will come across honest to the listener and it would be more believable.
QUESTIONS & PROVOKING THOUGHTS:
Asking questions in the song. Not necessarily providing the answer, but in asking, it provokes the listeners to ask themselves the question. Provoking thought is a good. Often a lyrically vague song can be applied to each individual in many different ways, based on their different life experiences and perspectives.
POINTS & CONCLUSIONS:
What's the point? Though points & conclusion lines are often found on the end line of a chorus, these can occur many times throughout a song, for example at the end of each verse. It's just a way of getting to the point lyrically and making it clear to the listener what you are talking about at any one time and where you are coming from as a songwriter.
A Syllabic approach is applying lyrics in a way that utilises each syllable of a word. For example each syllable within a word is associated with a note, Rap tends to be very syllabic and this approach is generally much more rhythmical sounding.
A melismatic approach is the stretching out of one syllable in the many notes, such as the approach often used by Christina Aguilera or Beyoncé.