The best way to evaluate a plugin is to simply open up its files and read the code.

After installing WordPress plugins we have consider the flowing questions that may arise they are:
•	Do JavaScript-based administrative functions still work?
•	Does your site slow down?
•	Does the plugin add warnings to the top of every administration screen?  If so this plugin needs to be configured or just invitations to buy things and/or promote the company on your social media networks.
•	 Does it add spam links to your source code?
•	 Check the site in another browser, one where you are not logged in to WordPress
•	Does it put ads on your admin screens—even those for other plugins’ settings.
•	Does it add a Dashboard widget full of links to the developer’s other products?
•	 Does it add text to your site’s footer without your permission?
•	 Does its settings screen blend in with the WordPress Dashboard, or does it look completely different.

For trouble shooting WordPress plugins we have to follow the after-mentioned things:
•	Deactivate the new plugin if there is any problem with it and switch to one of the default themes.
•	Install the Plugins Performance Profiler (P3) if the site is too slow. This plugin will scan the site automatically and report how the plugin affected the site’s that load time.

Installing WordPress using the Web Interface:
	Download a latest version WordPress from wordpress.org
	Check the basic requirement of database and PHP version
	Upload the wordpress folder in host
	Open WordPress folder using web browser
	Create a database
	Click on Let’s go button
	Set database information Database Name(that previously created), User Name, Password, Database Host and Table Prefix(optional) 
	Click Submit button
	Click Run the install button
	Set Needed Information Site Title, Username(Usernames cannot be changed), Password, E-mail (This information is editable) and Check Privacy check box 
	Click on Install WordPress button
	You can see Success! Page, So installation is successfully done.

Download theme files from www.wordpress.org/theme and upload theme to your wp-content/themes folder 
Or you can use the automatic theme installer.
	Install theme using by Automatic theme installer:
	Goto dashboard 
	Apprarance
	Themes
	On this themes screen select Install Themes tab, you will see a search screen
	Here, you can search for themes by name
	Select your desired theme and
	Click on install button