I already finished 'Remembering the kanji' about one year ago, but as the time passed my will of reviewing the cards decreased.
However I forced myself to not give up reviewing only to practice my writing and not forget the basic rules about stroke order.I knew that it was not the correct approach to the book, but I wanted to focus more on native speaker's material and so I started to read a lot everyday and overall I can say that I have improved.
In other words I wanted to learn onyomi and jukugo by a lot of input.
That being said, now I am writing this post because today I will restart Heisigs book again, but I will not rush like the last time(50 kanji for day) and I will try to learn only 25 kanji each day helped also by the fact that somehow I already know kanji better and it should be easier to reach the end of the book(I will use anki software).

I am going to start the book in the 'normal way', but during the last year it comes to my mind a little different approach that I will try to explain, altough I never used it.
What I would like to know from you is if you already tried a similar idea.

Method overview:
1-Consider kanji as simple characters with a list of onyomi attached and not consider their kunyomi(most kanji will have only a typical onyomi).

2-For every onyomi create an image to associate to it.
For example:
きゅう could mean ambulance because it appears in this jukugo 救急車(kyuukyuusha).
きょうcould mean dinosaur because of the jukugo 恐竜(kyouryuu).
You can also attach to the sound a completely unrelated meaning as long as it is easy to remember.

3-For every kanji create a story that will make you remember the sound image you created with the heisigs method.

With this you should be able to read most of the jukugo like if they were written in hiragana or katakana.
The only problem I can see is how to learn kunyomi and how to choose what sound read for a kanji with multiple readings.
However also 'Remembering the kanji' has his drawbacks that we all are aware of.

What do you think of this method?

like this? http://kanjidamage.com/

Yes, most Kanji have only a onyomi. However, but it must be remembered that there are some with no onyomi. Having one reading or the most common would seem to be a good idea. However, including multiple reading would also be useful.

Thank you I didn't know about the kanjidamage site.
The onyomi part is basically what I have described above apart from the fact that he links every onyomi to an english word instead of an image.
I think that an image should stick easier in the brain if fe follow the Heisigs philosophy, but his method seems to want you memorize more sides of a kanji, whereas I was content with just onyomi memorization.
I mean that it seems good to simplify japanese into a 'normal language' where you read a word and you only have to memorize the meaning.
Because I noticed that when I began to read articles from native sources, although I did study with the Heisig method I tended to not think about keywords, but only to view kanji as a mere character.
An improvement to my method could be that the story to recall the image associated to the onyomi has to make you remember also the meaning of the kanji or at least give you an hint.
As for the numbers of onyomi associated I think that it's enough the most common one, because when you will encounter an exception this will stick anyway just because it is an exception I think.(It's like some sort of hack to make a computer program work, but anyway...):-)

hmmm. Have you checked out the movie method one? I couldn't vouch for it effectiveness (I read it was onyomi-based if I'm not mistaken) as I am reduced to reading txt files (Revtk doesn't work on my phone and I couldn't afford to stay online a lot for ankiweb).