How optimization with my Linode 768 VPS?

my website is bulit with linux(CentOS),myswl,nginx and php.It has 10000IPS/day,20000PVS/day.How to optimization it, would somebody like to tell me?

php.ini

`[php]

engine = On
zend.ze1_compatibility_mode = Off
short_open_tag = On
asp_tags = Off
precision    =  12
y2k_compliance = On
output_buffering = On
unserialize_callback_func=
serialize_precision = 100

allow_call_time_pass_reference = On
safe_mode = Off
safe_mode_gid = Off
safe_mode_include_dir =
safe_mode_exec_dir =
safe_mode_allowed_env_vars = PHP_
safe_mode_protected_env_vars = LD_LIBRARY_PATH
disable_functions =
disable_classes =
expose_php = On

max_execution_time = 300     
max_input_time = 60    
max_input_nesting_level = 64 
memory_limit = 64M      
error_reporting = E_ALL & ~E_NOTICE

display_errors = On

display_startup_errors = Off
log_errors = Off
log_errors_max_len = 1024
ignore_repeated_errors = Off
ignore_repeated_source = Off
report_memleaks = On
track_errors = Off
register_globals = Off
register_long_arrays = On
register_argc_argv = On
auto_globals_jit = On
post_max_size = 50M
magic_quotes_gpc = On
magic_quotes_runtime = Off
magic_quotes_sybase = Off
auto_prepend_file =
auto_append_file =
default_mimetype = "text/html"
doc_root =
user_dir =
extension_dir = "/usr/local/php/lib/php/extensions/no-debug-non-zts-20060613/"
extension = "memcache.so"
extension = "pdo_mysql.so"
enable_dl = On
cgi.fix_pathinfo=0

file_uploads = On
upload_max_filesize = 50M
max_file_uploads = 20

allow_url_fopen = On
allow_url_include = Off
default_socket_timeout = 60

[Date]
date.timezone = PRC

[Syslog]
define_syslog_variables  = Off

[mail function]
SMTP = localhost
smtp_port = 25

[SQL]
sql.safe_mode = Off

[ODBC]
odbc.allow_persistent = On
odbc.check_persistent = On
odbc.max_persistent = -1
odbc.max_links = -1
odbc.defaultlrl = 4096
odbc.defaultbinmode = 1

[MySQL]
mysql.allow_persistent = On
mysql.max_persistent = -1
mysql.max_links = -1
mysql.default_port =
mysql.default_socket =
mysql.default_host =
mysql.default_user =
mysql.default_password =
mysql.connect_timeout = 60
mysql.trace_mode = Off

[MySQLi]
mysqli.max_links = -1
mysqli.default_port = 3306
mysqli.default_socket =
mysqli.default_host =
mysqli.default_user =
mysqli.default_pw =
mysqli.reconnect = Off

[mSQL]
msql.allow_persistent = On
msql.max_persistent = -1
msql.max_links = -1

[PostgresSQL]
pgsql.allow_persistent = On
pgsql.auto_reset_persistent = Off
pgsql.max_persistent = -1
pgsql.max_links = -1
pgsql.ignore_notice = 0
pgsql.log_notice = 0

[Sybase]
sybase.allow_persistent = On
sybase.max_persistent = -1
sybase.max_links = -1
sybase.min_error_severity = 10
sybase.min_message_severity = 10
sybase.compatability_mode = Off

[Sybase-CT]
sybct.allow_persistent = On
sybct.max_persistent = -1
sybct.max_links = -1
sybct.min_server_severity = 10
sybct.min_client_severity = 10

[bcmath]
bcmath.scale = 0

[Informix]
ifx.default_host =
ifx.default_user =
ifx.default_password =
ifx.allow_persistent = On
ifx.max_persistent = -1
ifx.max_links = -1
ifx.textasvarchar = 0
ifx.byteasvarchar = 0
ifx.charasvarchar = 0
ifx.blobinfile = 0
ifx.nullformat = 0

[Session]
session.save_handler = files
session.use_cookies = 1
session.name = PHPSESSID
session.auto_start = 0
session.cookie_lifetime = 0
session.cookie_path = /
session.cookie_domain =
session.cookie_httponly = 
session.serialize_handler = php
session.gc_probability = 1
session.gc_divisor     = 100
session.gc_maxlifetime = 1440
session.bug_compat_42 = 1
session.bug_compat_warn = 1
session.referer_check =
session.entropy_length = 0
session.entropy_file =
session.cache_limiter = nocache
session.cache_expire = 180
session.use_trans_sid = 0
session.hash_function = 0
session.hash_bits_per_character = 4
url_rewriter.tags = "a=href,area=href,frame=src,input=src,form=,fieldset="

[MSSQL]
mssql.allow_persistent = On
mssql.max_persistent = -1
mssql.max_links = -1
mssql.min_error_severity = 10
mssql.min_message_severity = 10
mssql.compatability_mode = Off
mssql.secure_connection = Off

[Zend Optimizer] 
zend_optimizer.optimization_level=1 
zend_extension="/usr/local/zend/ZendOptimizer.so"` 

**~~[b]~~nginx.conf  <e>[/b]</e>**

`~~[code]~~user  www www;

worker_processes 3;
worker_cpu_affinity 0010 0100 1000;

error_log  /home/wwwlogs/nginx_error.log  crit;

pid        /usr/local/nginx/logs/nginx.pid;

worker_rlimit_nofile 51200;

events
    {
        use epoll;
        worker_connections 51200;
    }

http
    {
        include       mime.types;
        default_type  application/octet-stream;

        server_names_hash_bucket_size 128;
        client_header_buffer_size 32k;
        large_client_header_buffers 4 32k;
        client_max_body_size 50m;

        sendfile on;
        tcp_nopush     on;

        keepalive_timeout 60;

        tcp_nodelay on;

        fastcgi_connect_timeout 300;
        fastcgi_send_timeout 300;
        fastcgi_read_timeout 300;
        fastcgi_buffer_size 64k;
        fastcgi_buffers 4 64k;
        fastcgi_busy_buffers_size 128k;
        fastcgi_temp_file_write_size 256k;

        gzip on;
        gzip_min_length  1k;
        gzip_buffers     4 16k;
        gzip_http_version 1.0;
        gzip_comp_level 2;
        gzip_types       text/plain application/x-javascript text/css application/xml;
        gzip_vary on;

        #limit_zone  crawler  $binary_remote_addr  10m;

        #log format
        log_format  access  '$remote_addr - $remote_user [$time_local] "$request" '
             '$status $body_bytes_sent "$http_referer" '
             '"$http_user_agent" $http_x_forwarded_for';

server
    {
        listen       80;
        server_name www2.mydomain.com;
        index index.html index.htm index.php;
        root  /home/wwwroot;

        location ~ .*\.(php|php5)?$
            {
                try_files $uri =404;
                fastcgi_pass  unix:/tmp/php-cgi.sock;
                fastcgi_index index.php;
                include fcgi.conf;
            }

        location /status {
            stub_status on;
            access_log   off;
        }

        location ~ .*\.(gif|jpg|jpeg|png|bmp|swf)$
            {
                expires      30d;
            }

        location ~ .*\.(js|css)?$
            {
                expires      12h;
            }

        access_log  /home/wwwlogs/access.log  access;
    }
#include vhost/*.conf;
include /usr/local/nginx/conf/vhost/www.mydomain.com.conf;
}<e>[/code]</e>`

**~~[b]~~my.cnf<e>[/b]</e>**

`~~[code]~~[client]
#password    = your_password
port        = 3306
socket        = /tmp/mysql.sock

[mysqld]
port        = 3306
socket        = /tmp/mysql.sock
skip-external-locking
key_buffer_size = 16M
max_allowed_packet = 1M
table_open_cache = 64
sort_buffer_size = 512K
net_buffer_length = 8K
read_buffer_size = 256K
read_rnd_buffer_size = 512K
myisam_sort_buffer_size = 8M

[mysqldump]
quick
max_allowed_packet = 16M

[mysql]
no-auto-rehash

[myisamchk]
key_buffer_size = 20M
sort_buffer_size = 20M
read_buffer = 2M
write_buffer = 2M

[mysqlhotcopy]
interactive-timeout<e>[/code]</e>`[/php]