The advice I always give my students is do not try to be a different person in English. In English and in your native language, you are the same person. So you should think about activities that you find interesting, entertaining or useful in your native language, and try to do those in English. For example, if you enjoy games and quizzes, you might enjoy a vocabulary app. But if you don't enjoy that kind of thing in your native language, you will hate it in English. Or if you love reading, you should do that in English. If you don't enjoy it much, you will hate it even more in English. Do the activities you enjoy. They all improve vocabulary. It doesn't really matter which ones you choose. The important thing is to choose activities that you will consistently DO. The other main reason to try to do the same things in English that you do in your native language is that you will learn vocabulary that you actually want/need. Good luck!

The best way to improve your English vocabulary differs depending on the person and whether they are a visual learner auditory learner and so on... But one key point is repetition, repetition, repetition. What my students find helpful is that I explain the words use them in context add some emotional value to them (for example telling a personal story using those words or an example that adds some emotion you link the emotion to the word.) And then I encourage repetition. There's also a really great message I adapted from a Russian polyglot which works well for learning vocabulary. It's very hard to explain though but is also a type of conversational class.

I can second flashcards. Rote SRS training every day can be boring, but it's _very_ effective. I recommend reading "Fluent Forever" for tips on how to make the flashcard creation process less boring and more effective at the same time. Other than that, I can recommend LingQ. I have started using it recently and I'm quite liking it so far.

Flash cards!