One of the most important part of learning English (or any other foreign language for that matter) is learning new vocabulary. It is one of the most important part but also the most difficult to accomplished.
There are many ways of learning new vocabulary but what I think is the most effective way is making your very own dictionary. It might be written by hand in a notebook (recommended) or simply created as a document file on your computer. Usually, whatever you do with your own hands ends up being mastered; and it is normal to be like that since you were actively involved in creating it.
Take your time and add every day at least three words to your dictionary with real life examples of the word’s usage, phonemic transcription so you learn how to pronounce the word correctly, and adding two or three synonyms might be of a real help.
For a better memorization of the new words you should use them in speaking and whenever you listen something in English try to listen for these words.
List memorization is the most common way of learning new words. There is a long list of words for the new lesson so we have to go home and learn it by heart. It is a good way of learning for a coming exam but for the long run it is really not that good. Learning vocabulary this way makes you remembering the new words for a short time (for an exam) but after that the words will be forgotten.
The easiest way of remembering new words for a long time is creating an example sentence with the word that is being learned. Create the sentence then write it in a notebook. Writing it in a notebook is not enough; now you have to read it aloud, so you can listen to it. You should create more than an example sentence with the same word.
Having your own dictionary is like a learning English diary which shows you your evolution from beginner to advanced learner.
Many teachers will advise you to try to guess the meaning of an unknown word from the context. I did and I can tell you that it is possible but not always. You may guess wrong and such thing is very difficult to correct. You don’t know a word?! Check a dictionary!!! That’s why dictionaries are made for and that’s why I advise you to create your own dictionary.
Another useful thing to know when it comes to creating your own dictionary and learning vocabulary is to learn root words. You might wonder what root words are. Well, root words are words without prefixes or suffixes. A very common root word is "act" which means "to do" (it has many more meanings and it can be a noun, verb, and verb phrase). There are many words that derive from the word "act"; few of them are: action, activity, transaction etc. Usually, words that derive from the same root word are better to be learned together because they often have similar meanings and spelling.
A word can take many forms. For instance, the word beautiful is an adjective, but the word beauty, which derives from beautiful, is a noun. As an adverb, you have the word beautifully. When you learn a new word you should learn all its other forms.
Don’t forget about suffixes and prefixes. So many English words are built with a root word and a suffix/prefix and understanding suffixes and prefixes is a very easy way to improve you vocabulary baggage.