How to improve WPS Startup Performance

You can improve portal startup performance by starting server in development mode.
You can achieve in two ways..
1) At the time of installing portal
2) From WAS in case you have skipped step 1.

1) At the time of installing portal

You can install portal either by selecting Full or Administrative option. If you install portal as Full option, you get all out of the box portlets and also administrative portlets, whereas when you install as Administrative option, you get only Administrative portlets.
So to get portal startup performance, select Administrative type of installation and just after this run the following scripts
For Windows
Run the ConfigEngine.bat enable-develop-mode-startup-performance -DWasPassword=password task from the wp_profile_root\ConfigEngine directory.
For UNIX
Run the ./ConfigEngine.sh enable-develop-mode-startup-performance -DWasPassword=password task from the wp_profile_root/ConfigEngine directory.

Note:- This task is for development only and is not recommended for production environments.
Read here for more Details

2) Secondly, if you have skipped step 1, you can always enable development mode from WAS.
Follow steps below
a) Login to WAS as admin
b) Go to Servers -> Application servers
c) Click on WebSphere_Portal.
d) Select Configuration tab.
c) select check box for "Run in development mode"
e) Restart Portal and server1.
Note:- Again, this setting should be enabled for development only and is not recommended for production environments.