This is the introduction, if you already know a few things about language families, skip to the second part. I usually write in English, even most of my personal notes are taken in this language and sometimes I find myself thinking in English. Nevertheless my native language is Romanian, spoken by no more than 25 million people around the world. In school I also studied French but because it never managed to conquer my complete indifference towards it, I now limit my vocabulary to oui and non, oh, and also je t'aime. Having a good understanding of Latin (Vulgar Latin is actually the foundation of Romance languages) will be very useful in learning the languages that formed from it, or were influenced by it, like Italian, French, Spanish, Portuguese and Romanian.
On the other hand, English, German, Dutch, Afrikaans, and northern European languages all share a Germanic background. Then we have Slavic languages like Russian, Polish, Serbian, Croatian, Bulgarian (the Southern Slavic are much the same). Going further in history these all have an Indo-European ancestor from which Persian also originated. Chinese, Japanese, Korean, which although developed in close proximity and have Chinese for inspiration are quite different from one another. Hindi is also Indo-European in origin although this doesn't mean a French man or a Russian woman can understand or find Hindi easy, we are talking about a tree where languages branched off in different times and evolved on their own. I am also going to mention Semitic and then I will stop with this introduction (I haven't even gotten into ancient languages and native American and Australian). Arabic and Hebrew are like brothers, while the first thrived and now has hundreds of millions of speakers, the second needed political intervention (Zionist movement) to be revived.
Not all languages are part of the 'tree', some don't seem to have any predecessors, like Sumerian.
2. So now what?
I don't have any special aptitude (and you don't necessarily have to) regarding learning a new language, I am studying Persian for three years with pauses now and then, I also began Chinese last year and plan to begin Russian (had to choose between Russian, Polish and Turkish). In my opinion you truly learn a new language if you are able to think in it, when you are no longer translating your thoughts and it all comes natural. Conflicts arise from misunderstandings an when people act without thinking first. It's very easy to see the mistakes in others than to correct your own issues, it's far more comfortable to badly judge someone just to make yourself feel better and it is sadly all too common when people close their minds, no longer seeing the truth and thinking goodness.
Learning a new language isn't a solution to everything, but it's a start, if you do it with an open heart, this journey will be its own reward. Put an hour into it every day, an hour when you give up on television for example. Buy/download a book about whatever language you choose, go find classes and attend them. Make this a fun thing to do and try to engage others, even if you know English, this isn't the only language on Earth.