One Way of Expanding Vocabulary.
I want to share my way of learning new words. I tried using flashcards, writing down on my notebook, using apps and others. But the best way that works for me is writing down on sticker note and sticking on everywhere at home like on a wall of kitchen, bathroom, bedroom etc. For instance, every time when I leave my home I see 2–3 new words that are sticked on a door and repeat them with example sentences. Then I learn them by heart after 2–3 days and change to the new ones. When you see and repeat things frequently it becomes familiar to you. Like that when I see new words everywhere in my home it makes me see and repeat them and after several days they become familiar. Moreover, I suggest you making this way as a habit. At first, it might seems not working. But if you do it over and over again after 30 days it becomes habitual.
Using this way I learnt about 1500 words for now. And I hope it will also help you to expand your vocabulary.