Each Joomla page should ideally process around 40 database queries per page. To check this:

1. Login to your Joomla Admin panel
2. Go to Site -> Global Configuration -> Site -> Debug Site = Yes.
3. Make sure "Override write protection while saving" is ticked; then apply the change.

NOTE: Once debugging is turned on, that will have an impact on your Joomla page load times so remember to turn it off afterwards.

Now everytime you load a page (frontend or admin) you will have the number of MySQL database queries displayed as well as all the individual queries at the very bottom of your page. Once you determine the number of queries being made per page, remember to go back into your Joomla configuration to turn debugging off.

Here are some additional suggestions on how to enable your Joomla website to load faster:

A. Joomla Caching

A cache is a temporary storage area where frequently accessed data can be stored for rapid access. Once the data is stored in the cache, subsequent requests can be made by accessing the cached copy rather than re-fetching or recomputing the original data. For instance, instead of hitting your MySql database with same queries over and over again, your data is stored to a local storage (in the Joomla cache directory) and retrieved from there, instead of from the database. This means that your database will perform better, and your website will feel faster, and be able to support more simultaneous users.

1. Login to your Joomla Admin panel
2. Start with Site -> Global Configuration -> Cache -> Caching = yes.
3. Make sure Override write protection while saving is ticked then apply the change.

B. Turn Off Unnecessary Stats

1. Login to your Joomla Admin panel
2. Go to Site -> Global Configuration -> Statistics -> Statistics = No. Make sure Override write protection while saving is ticked then apply the change.

C. Module Caching

1. Login to your Joomla Admin panel
2. Go to Modules -> Site Modules then go into each module seperately and look through the options most of these have the option to enable a cache as well. Enable the cache on every module that has the option.

D. Delete Unused/Unnecessary Joomla Modules, Mambots, Components

Even if they are unpublished some of these plugins can still be calling the Mysql Database due to inexperienced programming, better to get rid of the deadwood anyway for security as much as speed.
Delete all Joomla modules, components and mambots that are not being used. Also delete all the site modules that are not being used.

E. Optimise MySQL Database Tables

Optimise your MySQL database tables every so often:

1. Login to your Joomla's mySQL database via phpMyAdmin
2. Display the tables and then scroll down to the session table.
3. Check the check box next to the table (session table or any tables having overhead values) and select the Optimize option from the drop down select list.

F. Turn Off Error Reporting

1. Login to your Joomla Admin panel
2. Select Global Configuration / Server Tab / Set the error reporting to None.

NOTE: If your web page attempts to make any remote/external connections, your site may load slower depending on how quickly or successful the external connections are made.