This isn't fine tuning, just simple beginner things I've figured out.
Rates request by lines read per second without indexes since startup - i.e. damage rating. If your server is hogging CPU use this to figure out what indexes you need.
SET @uptime := (SELECT VARIABLE_VALUE
FROM performance_schema.global_status
WHERE VARIABLE_NAME = 'Uptime');
SELECT
digest_text,
count_star,
avg_timer_wait,
sum_rows_examined,
sum_no_index_used,100 - (100*(sum_no_index_used/count_star)) as no_index_percent,
/@uptime as requests_per_second,
count_star/@uptime as reads_per_second,
sum_rows_examined/count_star as read_per_query
sum_rows_examinedFROM (
select * from
performance_schema.events_statements_summary_by_digestorder by count_star
desc limit 50
as top_qs
) WHERE sum_no_index_used < count_star
ORDER BY (sum_rows_examined/@uptime)
DESC LIMIT 10\G