A lesson missed often requires at least double the time to sort through someone else's notes to find the information yourself. Each lime you revise, you remember more of what you learnt. Summarize the key points made. Include teacher's comment about important topics and likely exam questions. Be involved and alert.
Structure notes into main headings and sub-headings.
Insert notes under these headings. Use the original notes as much as possible. Rewriting is a waste of time. Use them in your independent study to record information for assignments and essays.