I think the first obstacle in learning Japanese is to remember all the kana. Do you guys have any effective way?
If you search for "hiragana drill" and "katakana drill", you'll turn up a whole mess of different web apps you can choose among. The important thing is to find a method that you will stick with and use. When I learned myself, I just wrote them over and over, pronouncing the sound aloud as I wrote each one. Take care to learn the correct stroke order, though, however you do it. It's important. Once you've learned them, you can find children's stories written all in hiragana to read for practice.
Using my method, I took 3 days to memorise the kana. It doesn't matter if you do hiragana or katakana first, since eventually you want to be able to read and write them both.
Write them out 3 times per character in sets of five, (or sets of three for the
や ゆ よ row and the
わ を ん row) As you write them, sound out the pronunciation in your head or actually voice them out.
I also used this site for learning.
Disclaimer: What's effective for one person may not be as effective for another.
Vowels: あ い う え お
K: か き く け こ
S: さ し す せ そ
T: た ち つ て と
N: な に ぬ ね の
H: は ひ ふ へ ほ
M: ま み む め も
Y: や - ゆ - よ
R: ら り る れ ろ
W: わ - - - を
The K, S, T, H groups can have dakuten, and are voiced to G, Z, D, B sounds respectively:
ga gi gu ge go: が ぎ ぐ げ ご
za ji zu ze zo: ざ じ ず ぜ ぞ
da dji dzu de do: だ ぢ づ で ど
ba bi bu be bo: ば び ぶ べ ぼ
The H group can have the maru, and is voiced to a P sound.
pa pi pu pe po: ぱ ぴ ぷ ぺ ぽ
Now realise that glides are a combination of the い column with the Y-Row.
きゃ きゅ きょ、 しゃ しゅ しょ、 ちゃ ちゅ ちょ etc.
Essentially you only need to remember 46 characters in each kana. Remembering patterns lets you have less things to memorise.
After writing them out a couple of times, take a break. After a certain threshold it becomes useless to write it out since you start to rely on short-term memory and muscle memory.
Repeat writing out the entire set every 2 hours or so. (You want your brain to actively try to recall how the characters look and sound like, instead of just following through a motion pattern with your hand)
Then once you think you have it memorised, use a flashcard program to improve your recognition speed.
Lookalikes to be wary of:
わ れ ね:
wa curls left,
re curls right,
ne has a loopy.
あ め ぬ:
a has a line on top,
nu has a loopy
chi look like mirror images
ru has a loopy
ソ（so） starts with the a small stroke down, then a stroke from top-right to bottom-left (The right side of the character is almost vertical).
ン（nn） starts with a small stroke down, then a stroke from bottom-left to top-right (The bottom of the character is almost horizontal)
シ ツ(Katakana): Look at your Numpad, I'll use the 1-9 to represent a grid. The approximate direction of how
シ(shi) is written: 7, 4, 1>2>9. Contrast this to
ツ(tsu): 7, 8, 9>6>1.
When there are lookalikes or particular ones you find don't stick, it's worth learning some words.
e.g. I remember finding ユ and ヨ (katakana "yu" and "yo") difficult to distinguish for a time, solved by learning the word ヨーガ (yoga)
Even with only a few hiragana, you can start putting together simple words like あおい。 You may find this helps you remember more easily than working on single kana alone.
There's a book called "Remembering the Kana" written by "James W Heisig". The method utilizes "imaginative memory". I.e. for every symbol you invent a detailed "story" or picture that ties symbol's meaning to the way it looks. The idea is that brain remembers fantastic stories immediately and doesn't forget them any time soon. This way you can learn character in one attempt. As far as I know, it is a well known memorization technique.
However, you'll still need to read through a book written in hiragana/katakana, because although you'll learn which symbol is which very quickly (and probably in one attempt), recalling anything learned by this method is not very fast, and you need to read through some text until your brain "Caches" meanings of new symbols.