I've studied English for ___ years, but I still don't feel like I can speak it very well...
Us language teachers hear this at least once a day, if not more, and it's completely normal for our students to feel this way. Learning a language is difficult and isn't something that you can just read and memorize. It's true that some people are better with languages, just like others are better with numbers, but fundamentally, to become very comfortable or even fluent in a language, you really need to dedicate a lot of time to it. Now, realistically speaking, most people don't have time to study 4-5 hours a day, even just finding 1 hour a week to dedicate to your studies can be difficult. Of course, any time that you can dedicate to learning another language is awesome, but you need to be realistic with your goals - if you can dedicate more time, you will learn faster and vice versa.
If you really want to become as fluent as possible in the language you are learning though, you really must consider doing some type of immersion experience at some point. For most adults, a 6 month to a year exchange program isn't feasible, but have you ever considered taking advantage of your summer holidays to do a 1-2 week immersion course? Sure, you won't become fluent in 2 weeks, but you'd be surprised how much you'll pick up. Most courses for adults are designed to give you 4-5 hours a day of lessons, allowing you to have the rest of the day to take trips to visit the place where you are staying. Of course, the more you pay, the more activities will be included, but even just taking a walk around a new city, reading the signs, taking the bus and listening to people around you is a way to soak up some new vocabulary. To give you an example, the British Council has a page dedicated to helping you organize this type of holiday (then even have holiday options for the whole family!), but you could find the same type of program for the USA and Canada, Australia and probably even New Zealand!
Do you ever wonder how children pick up languages so quickly, just by watching TV or having a babysitter who speaks another language? It's because they have no choice but to try to understand what's going on around them, and of course because they are like sponges. Now, of course, for us adults, it's a bit more complicated, but if you really want to bump up your level, you could always consider doing a full immersion experience for a few weeks. This is what many high school students do, they stay with a host family for a period of time, and this leaves you no choice but to interact and try to learn as much as you can in the short time that you are there. As an adult, this experience can be a little more uncomfortable, as most of us have our set routines, likes, dislikes, etc., but if you are really adamant about learning a language and experiencing the culture that surrounds it, you might just consider trying out an experience like this! Lingoo offers this type of experience and makes it very easy for you to organize your holiday.
Motivation is key
As I said earlier, this type of holiday is not for everyone, so don't despair if it just isn't for you. Keep studying, watching Netflix, talking to tourists and of course taking your English lessons, because once you put your mind to it, nothing is impossible!
feasible: possible, realistic
pick up: phrasal verb - to learn
soak up: idiom - to absorb information etc.
bump up: phrasal verb - to improve
put your mind to it: idiom - to decide to do something