When a lot of plugins are installed on your website, they allow you to enrich your WordPress website functionality and include a variety of custom options for you and your website visitors. The side-effect is that heavy and resource-capacious plugins may slow down your website by consuming the CPU and I/O resources allotted for your website.
To optimize your website efficiently, you should understand which exactly plugin is consuming up most of the resources. To check it, you may use P3 (Plugin Performance Profiler) plugin for WordPress. When scanning your website with this plugin, it shows a diagram with the contribution of each plugin to the website loading time and the relative time each plugin loads. It will allow you to determine which plugins make your website load slower and decide whether they can be disabled.
There is another useful plugin for WordPress – Plugin Organizer. It allows you to disable plugins selectively and rearrange the order your plugins are loaded in. It can also improve your website performance.
Finally, once all these measures are implemented, you may check the optimization level of your WordPress website with GTmetrix plugin for WordPress.