Kanji is arguably one of the most difficult part of learning Japanese. I am sure it is extremely hard to memorize even a single kanji character, as they often have multiple pronunciations with so many strokes. But did you know that kanji have something in common in terms of their components and definition? As long as you know those common features, you can somewhat guess the meaning of a kanji, even if you come across an unfamiliar one. Once you get the hang of it, I am sure learning Japanese will become much more interesting and fun!
Kanji characters are made up of various components called "部首" (radicals, pronounced "bushu"). A character is typically divided vertically into two sections, with the component on the left called "hen" and the component on the right called "tsukuri." For example, the kanji for "休 (to rest)" is made up of the radical "亻" and "木". The radical "亻" is called "nin-ben," which means "person/human." Many kanji that use the radical "亻" are related to people, such as "体 (body)," "仕" part of "仕事 (work)," as well as "働く (to work)." As for the kanji "休," it is probably easier to remember it as a "人 (person)" is "休んでいる (resting)" next to a "木 (tree)!"
In this article, I would like to introduce some of the radicals used in kanji and the meanings behind each one of them. All the kanji that appear in this article are typically introduced at elementary schools in Japan.
"San-zui" resembles water droplets splashing. Since this radical refers to water, many of the kanji that use this radical also have meaning related to water. For example, there are kanji for "海 (umi; ocean)," "泳ぐ (oyogu; to swim)," "洗う (arau; to wash)," "泣く (naku; to cry)," and so on that use san-zui.
On a side note, most public toilets in Japan are equipped with an e-bidet seat that have many button options. If you have ever traveled to Japan, you might have had trouble figuring out which button is the flush button. If so, try looking for a kanji with san-zui. I am sure you will be able to find the kanji for "流す (flush)" or "洗浄 (wash)," so press that button.
"言" is a kanji character that means "言う (iu; to say)." It is also used in "言葉 (kotoba; word)." Thus, there are many kanji related to "language" which use this radical. For example, there are kanji for "話す (hanasu; to speak/talk)," "記" part of "日記 (nikki; diary)," "語" part of "日本語 (nihongo; Japanese)," "説" part of "説明 (setsumei; explanation/to explain)," "論" part in "論文 (ronbun; thesis)," and so on.
In Japanese, there are many kanji related to "手 (te; hand)" as well as kanji that describe actions using your hands. For example, there are kanji for "指 (yubi; finger)," "拾う (hirou; to pick up)," "持つ (motsu; to hold)," "投げる (nageru; to throw)," and "打つ (utsu; to hit)." It might be easier to remember these kanji by remembering them in sentences, such as "拾う (picking up)" something by "合わせて (awasete; joining)" your "手 (hands)."
This radical is called neither "へん (hen)" nor "つくり (tsukuri)" but is instead called "冠 (kanmuri; crown)" as it is on the upper part of the kanji. "冠" means "crown," which is a headpiece worn by someone to indicate their social status or rank. Since it is derived from the shape of a house roof, there are many kanji associated with houses that use this radical. For example, "家 (ie; house)," "室" part of "教室 (kyōshitsu; classroom)," "宿" part of "宿泊 (shukuhaku; lodging)," "宅" part of "自宅 (jitaku; one's own house)," and more.
Shells were used as a form of currency in ancient China. For this reason, many kanji characters which use "貝 (kai; shell)" are related to money and wealth. For example, there are "買う (kau; to buy)," "貸す (kasu; to lend)," "貯" part of "貯金 (chokin; savings/to save)," "財" part of "財布 (saifu; wallet)," "費" part of "費用 (hiyō; expenses)," and so on.
The kanji "病" in "病気 (byōki; illness)" is read as "yamai" in kun-reading (訓読み). "Tare (垂)" is the part of the kanji located on the upper side to the lower left side of the character. This radical is derived from a person lying in their bed, sweating. There are many words related to illness that use this character. For example, "病院 (byōin; hospital)," "痛い (itai; pain)," and so on. Although the following kanji are typically taught in junior high schools instead of elementary schools, there are also "疲れる (tsukareru; tired)" and "症" part of "症状 (shōjō; symptom)" which are also kanji that use "yamai-dare." Many of the kanji that use "yamai-dare" require multiple strokes and are difficult to read, but even if you do not know how to read them, you can guess that they probably have something to do with "illness."
So far, I have introduced the meanings of several components called "部首 (radicals)" that are used in kanji. I am sure it will make it a lot easier for you to remember kanji if you can recognize the common meanings behind them. There are many, many different types of radicals used in kanji, so I recommend that you look into what the radicals of the kanji you have just learned is, and what meaning they might have. I am sure you will encounter many more kanji in the future, but please pay attention not only to the meaning of the kanji themselves, but also to the meaning of the radicals used in those character. There are many different approaches to learning kanji, but a good way might be to try to sort and memorize them based on the radicals they use.