Daichi wrote:

Knowing what pitch means is pretty simple. Knowing how the hell to control that factor of your voice is not.

It's effectively the same as singing. Each note is different because constriction of the vocal cords yield a different pitch. As for Japanese pitch per se, low and high are often quoted as being do and mi (or C and E), but this is only a guide.

I'm not Daichi, but I had a similar problem with pitch. 

If Daichi is anything like me, than describing pitch in relation to singing is not going to help.  I can't sing.  At all.  Not even a little.  I can't hear pitch and I can't reproduce it.  If you ask me to sing "do re mi fa sol la si do", I might be able to say, "do re mi fa sol la si do", but pitch-wise you'll probably be hearing something like "do do -1ti re sol sol ti ti". 

My suggestion to Daichi is to get a native speaker to correct you.  I've spent multiple hours over multiple days working with native speakers on correct pitch.  I am now to the point where I can hear it if I'm specifically listening for it.  I can also usually mimic it.  But I still don't get it right if I'm talking on my own.  And I still can't sing at all.

It's a tough process if you have no musical ability :-\

If you wanted to learn pitch in general, I would recommend taking singing lessons.  Your teacher should correct you on things like this.  I've often thought about doing this, but I don't have the money/time/motivation.

nadiatims wrote:

Just regularly have conversations with people, and you'll start to pick up their speech habits, words phrasing and also pitch.

I believe AlexandreC argues that this is not the case.  From my personal experience (and seeing those around me), I will have to agree.  There are a lot of people in Japan who are relatively fluent that don't use correct pitch.  For some people, pitch can't be learned through immersion.

Marble101 wrote:

If I hear a word and try to mimic it as close a possible, would that suffice, or would I need to specifically train my ear for pitch accents.

One should probably at least be aware of the basic pitch patterns and know that they do make a difference. Back when I wasn't aware of them I would work hard to perfectly reproduce the consonants and vowels, but I considered mimicking the native speaker's pitch contour about as important as imitating the timbre of their voice or the facial expression they are making when saying the words, i.e. totally irrelevant.

Marble101 wrote:

If I hear a word and try to mimic it as close a possible, would that suffice, or would I need to specifically train my ear for pitch accents.

How do you know what what parts to mimic and what parts not to mimic? If I tell you "is that a dog?" and you learn to mimic dog, will you always say it with a rising tone? It takes a lot of exposure to determine which must be copied and which is flexible, and when it comes to pitch, most foreigners assume this up and down movement has to do with sentence level intonation when it's actually part of the word itself.