It depends on the word.

If it is a word that is frequently used in the language, I don't do anything special to learn it. By just being exposed to the language, you will hear and use the word often so you do not need to do much to remember it.

There are words that are similar or the same to my target and my native language ("cognates"). Again, with these words, I do not do anything special since it is already similar to a word of my native language. I just take note of pronunciation or spelling differences.

If it is a word that is not used all of the time but is important to know, I try to form some association with the word. One method is to associate the sound of the word with another word I know. For example, I wanted to learn the Russian word for "bed". This word is кровать. However, the sound of this word reminds me of the French word for "tie", which is "cravate". So, I imagined a bed made of colorful ties. The Spanish word for pregnant is "embarazada". This reminds me of the English word "embarassed". So I imagine a woman who is embarassed of her pregnancy.

Another method to form an association is to break apart the syllables of a word, associate each syllable with a person or thing that the sound of the syllable reminds you of and form a ridiculous relationship between then. The more ridiculous the relationship, the easier it will be for you to remember.

Last method is to create my own sentence using the word and try to relate this sentence to something I do or have done during the course of my life.

I sometimes use a spaced repetition program like Quizlet (I'm not a fan of anki's algorithm).

I never do rote memorization though. It takes too much time and I forget too easily.

I don't memorize individual words. I memorize whole sentences. Words are much more easily remembered when they are in context.

Just think how to used those new words in the reality situation, and make a sentence by those words, if those words appear in your conversations by coincidence, you got it !

I try to learn 20 new words at the end of each day but you can learn as many or little as you want.

I also use ANKI and make stories for the sound of each word to help me remember. If the the word sounds like something else in your language then imagine a story with that word to help you remember.

Review often. Teacher yourself like a teacher