Learning languages is both easier and harder than most people think. I know two: English and Spanish. My knowledge of Spanish is rapidly rusting from lack of use, so I won't trust my own capabilities to translate it.
On the easy part, it's about learning new labels for things, aka "Vocabulary," and the way the words fit together, or "grammar." Unless it has some odd features, like a different relationship to time, or something along those lines, but most of the top twenty I listed don't suffer that.
If you take a class, they start off with some handy phrases to introduce yourself.
Hello, my name is [my name].
Hola, me llamo [my name]. (Ola, may yamo [my name].
Hallo, ist mein Name [My name]. (Hallo, ist mine na-me [my name].)
你好，我的名字是 [My name]. (Ni Hao, Wo Jiao [my name].)
こんにちは、私の名前は[My name]ある. (Konichiwa, watashi wa [My name] des.)
Здравствулте!, Меня зовут [my name]. (ZDRASt-vooy-te. menya zavoot [my name].)
Having managed that much, research into vocabulary and grammar can begin.
On the hard end of this, sometimes the grammar or other features can be really strange. Or, sometimes in slightly related languages there are "false friends" that seem like one word, but would be understood completely differently in the new language.
As an example of grammatical weirdness, (at least from the perspective of English speakers), Russian, the last language on that list I just gave you, has noun declension. One can actually arbitrarily rearrange the words in a sentence and still be understood, if maybe a little odd sounding, but one must modify nouns to explain how they fit in the sentence. Like "The cat ate the rat" would have a modification to "cat" to show that it's doing the eating, and "rat" to show that it's being eaten. Presumably Russian speakers find it equally baffling to not have to do this. (Or perhaps some other feature of English is equally confusing?)
Or tonal languages. The third language I listed there, Chinese, is tonal, and words must be spoken at the correct pitch or they become completely different ones. The syllable "ma" is "horse," "Mother" or "?" depending on what tone it's said at. Baffling for English speakers, though not terrible to adjust to. Meanwhile, Chinese speakers tend to be baffled by English's overcomplicated grammar.
Mad Engineering proposes language tapes that drill a person on phrases, using recordings from native speakers. At least, to start with. Vocabulary must be drilled, grammar studied, and common pitfalls avoided.
Common pitfalls include:
* Translating everything back to your own native language before responding, which will be obvious because you will be 5 minutes late in all responses. You learned your native language by attaching labels to ideas. Your second language should be attached to those ideas as well, not your first language.
* Trying to relate it to your native language, because it isn't. Your native language's grammar doesn't apply. Mnemonics are a phenomenally bad idea. One language teaching book had the example of a (fake and invented for demonstration) foreign word of "patsa." One should not substitute "pasta" to remember it. (That being a real word in English.) Because the substitute is wrong. (I hear many many stories of English teachers in Japan who say they always has a student who does this, and winds up with a barely understandable "katakana English." And then whines when teacher refuses to do the same.)
* Not practicing. What you don't keep fresh, rots and rusts.
* Trying to do too much too soon. You'll have to spend a lot of time fumbling before you can be fluent.
As hard as I've painted learning another language, it is a rewarding procedure. It opens new worlds of thoughts and people to you that were inaccessible before. And if you gain nothing else, a profitable life of a translator could serve you well, I suppose.