If you are here that means you already know what is a TLD(Top Level Definition).
To include a TLD in Liferay at root level or you can say a portal level tld, you can follow the steps which will help you to create one on your own.
1. Create a hook name mytld.
2. Create mytld.jsp at /docroot/web-inf/jsps/html/taglib/ui/mytld/mytld.jsp.
3. Create an ext named mytld ext.
4. Move to web.xml by /docroot/web-inf/ext-web/docroot/web-inf/web.xml in ext.
5. Put below lines in web.xml.
<?xml version="1.0"?>
<web-app version="2.4" xmlns="http://java.sun.com/xml/ns/j2ee" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://java.sun.com/xml/ns/j2ee http://java.sun.com/xml/ns/j2ee/web-app_2_4.xsd">
<jsp-config>
<taglib>
<taglib-uri>http://liferay.com/tld/ui-ext</taglib-uri>
<taglib-location>/WEB-INF/tld/liferay-fc.tld</taglib-location>
</taglib>
</jsp-config>
</web-app>
6. Create a corresponding java class for ur taglib(if required) at /docroot/web-inf/ext-util-taglib/src/com/liferay/taglib/ui/MyTld.java in ext.
7. Write required code.
8. Move to /docroot/web-inf/ext-web/docroot/web-inf/tld/liferay-fc.tld.
9. Put below lines in liferay-fc.tld.
<?xml version="1.0" encoding="UTF-8"?>
<taglib>
<tlib-version>1.0</tlib-version>
<jsp-version>1.1</jsp-version>
<short-name>my-tld</short-name>
<uri>http://liferay.com/tld/my-tld</uri>
<tag>
<name>foodcourt-discussion</name>
<tag-class>com.liferay.taglib.ui.FoodCourtDiscussionTag</tag-class>
<body-content>JSP</body-content>
<attribute>
<name>attribute-name1</name>
<required>true</required>
<rtexprvalue>true</rtexprvalue>
</attribute>
<attribute>
<name>attribute-name2</name>
<required>true</required>
<rtexprvalue>true</rtexprvalue>
</attribute>
</tag>
</taglib>
10. Deploy your ext.
11.Deploy your hook.
12.Restart your server.
12.Your new tld is ready to use.
Please let me know, if there is any concern about this Blog.