Community will really appreciate if you can elaborate your question instead of aem .
Also since page load performance is very generic question, there is no simple answer to it. Please provide more details like what type of page it is, do you have dispatcher? How many request are going back and forth? How much memory you have provide to AEM?
There may be multiple reasons why your page is taking so long to load, you need to determine where the issue lies.
For example, the issue may be with the page rendering, you could have components code that is taking a long time render or it could be because your page is heavy with front end code.
You can use the link Scott shared above to determine where the issue lies, but, as well as front end analysis, you will want to use a tool such as rlog.jar as described in Monitoring and Maintaining Your CQ instance to determine how long it actually takes to render the page from AEM.
On the author instance you can also use the developer mode to check the performance of each component: Developer Mode.