Recommended mySQL Settings

Hi guys.
Just wondering if there are any "mySQL Gurus" here who can help me out. I ran the advisor in phpMyAdmin and it's recommended a few changes. However, not being a mySQL person, and having asked the SiteGround people, they have asked I ask the "developer" of my script. The Advisor is stating the following:

Issue
Less than 80% of the query cache is being utilized.

The query cache size is above 128 MiB. Big query caches may cause significant overhead that is required to maintain the cache.

{tmp_table_size} and {max_heap_table_size} are not the same.

MyISAM key buffer (index cache) % used is low.

The rate of opening tables is high.

The rate of opening files is high.

The InnoDB log file size is not an appropriate size, in relation to the InnoDB buffer pool.


My current mySQL config is:

datadir=/var/lib/mysql

socket=/tmp/mysql.sock

old_passwords=1

ft_min_word_len=3

#safe-show-database

skip-name-resolve

max_connections=500

max_connect_errors=25

connect_timeout=10

interactive_timeout=20

wait_timeout=50

delayed_insert_timeout=10 

join_buffer_size=1M

max_allowed_packet=8M

myisam_sort_buffer_size=1M

sort_buffer_size=1M

read_buffer_size=1M 

read_rnd_buffer_size=2M 

table_cache=2048 

thread_cache_size=192 

thread_concurrency = 4 

query_cache_size=256M

query_cache_limit=32M 

query_cache_type=1 

tmp_table_size=128M

max_tmp_tables=10 

slow_query_log=1 

long_query_time=1 

slow-query-log-file = /var/lib/mysql/mysql-slow.log 

old-passwords = 1 

log_err = /var/lib/mysql/mysql.err 

innodb-file-per-table=1 

character-set-server=utf8 

collation-server=utf8_general_ci 

innodb_buffer_pool_size = 256M

innodb_log_file_size = 5M

key_buffer_size = 128M

bulk_insert_buffer_size = 16M

innodb_thread_concurrency = 4

innodb_autoinc_lock_mode = 0

skip-external-locking

innodb_doublewrite = false

low_priority_updates = 1

innodb_support_xa = false 

max_write_lock_count = 10

innodb_flush_log_at_trx_comm = 2

innodb_max_dirty_pages_pct = 40

innodb_io_capacity = 400

innodb_write_io_threads = 4

innodb_read_io_threads = 4

innodb_adaptive_flushing = 1

innodb_adaptive_flushing_method = estimate

innodb_flush_method = O_DIRECT

open_files_limit=5340

[mysqld_safe]

log-error = /var/lib/mysql/mysql.err

If anyone could help me out with the options I should be using, I'd appreciate it.
Thanks
Dave