Learning to craft a good song is a skill that can be developed with a bit of patience and practice. Arguably, one of the most important aspects of a great song will be the lyric. In fact, many successful songwriters feel that the lyrics are the most important aspect of the process; so writing meaningful lyrics could be a vital skill for any musician or songwriter.
Many tunes are developed around the lyrics, so this is an aspect that needs to be kept in mind. Also, like all writing in general, it is best to operate from what you know, so making lyrics personal has value as well. Write about what is important to you, yourself, and the universality of the message will become apparent.
And do not be overly concerned with rhyme schemes are poetic language. While it can be useful to keep them in place, it is certainly not necessary. What is more important for song writing is a sense of rhythm. Write lyrics with meter and flow in mind in order to make them adaptable to music.
Language is important, however, for the singing voice. For instance, you do not want to end verses on hard consonants, or try and write with multi-syllabic words that may not work well while singing. Keeping lyrics simple is important, regardless of the complexity of the subject matter.
And in the end, it is the subject matter that counts for most. Lyric writing tends to be a personal journey for most. What makes for a good song is something meaningful. For the writer, this will mean something that is personally meaningful. Emotions are universal, so if one can take their own life experiences and put them in a relatively simple and rhythmic form, the lyrics will be meaningful to the listener.