I have always found learning different languages exciting and fun - difficult - but I enjoy it. I've even been told that I used to read a German phrase book before I went to sleep. But it feels very few people want to learn even one language besides the one they've grown up speaking.
I have heard a lot of people say "What's the point?" or "Everyone's speaking English now." The only problem is that not everyone is learning to speak English. Even so, if someone from Brazil or China can take the time to learn English and make it easier for a native English Speaker, then shouldn't we show them the same courtesy? Not only will it make communicating easier for those working aboard but it will also show the citizen of any country that you respect not only their country but also their culture. One thing that I regret about living in Saudi Arabia is that I never learned to speak Arabic - though to be honest, I was under twelve while I was there but I did learn how to say "Thank You".
The best way to learn a foreign language is to immerse yourself in it. You could try reading books or watching films in the language. It's usually easier to read or watch them in English first though. This will allow you to read and hear the language that you wish to learn not only in your own time, but also at your own pace. Though you should note that languages like Mandarin and Japanese, it is incredibly difficult to learn in terms of reading and writing without a native speaker to help you out.
You need to set yourself a schedule for learning the language though. Sitting down and going through it for half an hour to an hour, will allow it to sink in better, which in turn, will enhance your proficiency. Try buying coloured cards or post-it notes and place them at various points around your home with different words or phrases. Put them in places like kitchen cupboards or on the TV. Places you know you’ll find them.
If your learning a language at school, put all of your worksheets and vocabulary sheets in a file, but as you go along write out things like grammar or vocab on a separate piece of paper, but set it out in way that you know will help you learn it. If it’s speaking that you are having trouble with, then ask for extra help. An extra half hour a week where you sit down and speak to the teacher in your chosen language should help.
Alternatively, if you have friends or family who can speak the language to a native level, then spend time talking to them. I would also recommend finding a native speaker if you are teaching yourself.
Those are my tips, but at the end of the day you are the only person who knows how you learn. You are the only one that can push yourself to learn a new language.