Difficulty of Creating Backlinks Through Blog/Forum Posts

Hello guys. I have a couple of questions regarding the difficulty of getting most comments and posts approved.

Just a short introduction: I've been working out as an SEO guy for quite some time now, promoting a travel site on the web. I am aware of the different methods of gaining backlinks (article submission, social bokmarking, link exchange, social media, directory submissions, link wheel) but for this task of mine, I am limited to create backlinks through blog comments and forum replies/posts using anchor texts and links, not the URL.

I am also aware of the web etiquette of getting backlinks through forum and blog posting, i.e. contribute something valuable to the topic at hand (not just saying "great post" or "thanks" and then dropping your link like a hot potato), avoid using your keyword as your username, incorporate your keyword seamlessly into your post as to make it appear natural, observe other rules and regulations on the blog or forum board, post on blog related to your keyword, etc.

Given these terms, I simply find it hard to secure backlinks by exclusivey posting on blogs and forums.

Here are some of the techniques I've learned and acquired with regard to searching for relevant forums and blogs using Google:

* keyword + blog/forum
* keyword "post comment/add comment/post new topic"
* "This site uses KeywordLuv. Enter YourName@YourKeywords in the Name field to take advantage." + keyword
keyword intitle:blog/forum inurl:blog/forum
* dofollow blog/forum search engine

Also, I've downloaded free softwares, Fast Blog Finder at Comment Kahuna, that searches the web for blog posts that I could comment on.

(There are other methods outside the oned listed above, of course, but thse are primarily the ones I use that have relatively worked in my experience. Maybe if you have other suggestions, please feel free to reply.)

Anyway, even when using these search queries, 90% I come across blogs that are moderated tightly or probably the opposite that most of my posts are disregarded, flagged, or deleted, despite the quality of my post, i.e. constructive, related to the topic, and definitely not spammy.

My observation is that building backliks using blogs and forums alone is highly difficult, if not next to impossible given the fact that most blog owners have become stricter with regard to allowing comments with the purpose of getting backlinks, although I have to admit that dealing with forums a lot easier. Regardless, I'm supposed to make this seeming impossibility into reality, and as of this moment, I'm stuck.

Having said all these, here are my questions:

1. Am I doing anything wrong with my techniques or simply something that I'm missing?
2. Is it actually possible to have an effective backlink strategy by doing blog and forum posting?
3. Help, anyone?

Thanks in advance and my apologies for the lengthy post.