Does spamming keywords actually work?
Any general advice would also be appreciated
Craft the document such that it presents you in the best possible light for the job you are seeking without lying.
Describe not only what you did, but what _benefit_ these actions had on the business, technology, team, etc. Provide facts, data or evidence if you can, rather than hand-waving.
Note also that resumes/CV have different conventions in different regions/countries - with the US favouring a much more precise format (one-pager) whereas Europe tends to go for no more than 3 pages.