Grammar JLPT Level N3 - Lesson 6

的(てき) is a 接語尾(せつごび) (suffix) in Japanese that has two primary uses. The first use is very similar to 'as' or 'for' in English, and means 'considering/within the category of (A), (B)'. The second use primarily relates to people, and will be covered later. As a single word, 的(てき) is often likened to adjective endings such as '~ly', '~like', and '~al'.
To use 的(てき), attach it to the end of a noun that you want to express as being the focus point of either a verb or a noun that will come later in the sentence. When describing a noun, 的(てき) will be followed by な (meaning that it becomes a な-Adjective). When describing a verb, it will be followed by に (making it an adverb).

• そんな感情(かんじょう)的(てき)にならなくてもいいのに。
  You don't have to get that emotional. (Speaking in terms of emotions, there's no need to get like that)
• フィルターは定期(ていき)的(てき)に掃除(そうじ)してください。
  Please clean the filter regularly. (Speaking in terms of regularity, please clean the filter as such)
• それは個人(こじん)的(てき)な考(かんが)えですよね？
  That is a personal way of thinking, isn't it? (Speaking in terms of individuality, it's that kind of thought, right?)
• さっきなんかの宗教(しゅうきょう)的(てき)な人(ひと)たちが家(いえ)に来(き)た。
  Earlier, some religious people came to the house. (Speaking in terms of religion, some people like that came earlier)