You can perform link-building by following strategies:-
01) Article Submission
Waste of time. Why write for others ? If you are going to write them, write them for your site. Get the full PR and links, not some other site.
02) Social bookmarking Submission
Okay[ish] for traffic, but not in the way of decent links. If Fred Bloggs was going to give me a link, I'd prefer it to be from their own site, not some third-party social site.
03) Directory Submission
Decent ones are few and far between. Traffic will be low, and so will any PR. Time would be better spent elsewhere.
04) Forum posting
New name for Guestbook spam. You may get a bit of traffic, but this thread is about links, not traffic. (This thread should be about useful links, not any old link.)
I see. Create a site, then create a blog to promote the first site. hmmm.
Give it time, links from blogs will become devalued.
06)Competitor follow up
07) Press release Submission
Again, press release will/may gain you some traffic, but you are one about links. To me, press release means "paper media" ie, books, papers etc. A link from a newspaper will only inform the reader where to go.
I had to laugh at this one.
One links page. Looking for links. Single, non-smoker. GSOH. Please link back if you're serious.
09) File sharing
I am yet to come across a file-sharing site that doesn't break copyright laws.
10) Blog Commenting etc.
Same as #4... New name for Guestbook spam.
...blog creation and forum posting these strategy will give you high SERP results within few time duration.
More likely to be seen by Google etc as a spammer, and low quality.
Each to their own, but I would never follow the suggestions you've given.