Define Your Goal

When studying Japanese characters, you should have a goal in mind for your proficiency. Often, a certain approach to learning is suitable for one level of proficiency, but not another. Proficiencies can be seen as spanning a spectrum:
  1. Handwritten proficiency: ability to read and write cursive forms.
  2. Printed-word proficiency: the ability to recognize print forms and write them if given the meaning and a pronunciation.
  3. Printed reading proficiency: recognition within certain contexts.
You should match your study methods with your goal. If you're serious about Japanese, printed- word or higher is the right goal. Full printed-word proficiency in less than two years is attainable if you: 
  1. Work consistently.
  2. Learn the building blocks.
Work consistently As a student spending 10 minutes a day, learning 5 kanji a day, six days a week, will cover all Joyo Kanji in just over a year. Once you get printed writing proficiency, you basically get reading proficiency for free.

Why you should learn kanji by component building-blocks

if you start out learning kanji by component building-blocks, not only are you learning mnemonics for remembering the kanji, but you are also getting a cognitive head-start on rote learners. Research on eye fixation shows that proficient readers of recognize kanji by analyzing it into component characters.

Some approaches teach meaning only, without teaching pronunciation, but research on how readers process phonetic information in characters shows that the phonetic component of a kanji is often more important for reading comprehension than the radical. GeneticKanji will teach you the phonetic component.

Yet another benefit of learning kanji by components is that you will be able to learn cursive kanji naturally. I was able to teach myself cursive kanji after only 1 additional month of study from a cursive textbook, and then became more proficient after writing notes for my job in Japanese.

Other Tools

If your goal is to read kanji, but not to write, you might choose other approaches. Beware, though, that learning to read is cognitively different from learning to write, and doesn't  guarantee that you'll correctly recognize the characters when there is a shortage of contextual information (as in short text messages, newspaper writing, or terse legal documents.)

Flashcards and Software Flashcards

Flashcards or software flashcards can be a good way to drill for and confirm recognition, but do not teach how to distinguish between similar Kanji. You may be able to read 漠然 and 漢字, but not tell the difference between 漠 and 漢. 

Manga

Manga will teach words that are actually used in conversation, and the Kanji frequently have furigana written next to them to indicate the pronunciation. Avid readers of Manga with an eye toward learning kanji can develop good reading proficiency, but the print is often small, and the forms are difficult to grasp, unless one has learned to break Kanji down into its component parts.

Meaning-only Textbooks

Some kanji textbooks stress meaning, and omit pronunciation information. These can be very good if they break Kanji down into their component parts, but do not give you the ability to use the pronunciation itself as a memory tool.