Improve less Access Disk and memory my ratio bad

hello,

    I try to improve the disk's access number :

i notice that i have plenty of number access disk comparing my access memory then :

1 - i would like understand how may i improve it and by which method i could improve it.

2 - i would like less my %bad ?

3 - have i my tablespace of data or indexe unorganized ?

4 - have i to increase the number of read per block ? by  db_file_multiblock_read_count = 12 ?

what do you think ?

thank you for your help.

regards

JP

I executed this query then :

select
   buffer_gets,disk_reads,executions,b.piece,((disk_reads*1000)+buffer_gets)/tot.sumed*100  "% Bad" ,b.sql_text