How to build links for new website?

submit your site in directories and links in forum signatures helps a lot in building PR. Just wait for the PR update and you may see the changes

Firstly, don't worry about PR too much right now. The first reason is because it's just not all that important. Try to ignore it as much as possible. Sites with "good" PR can have poor actual rankings and sites with poor PR can have good rankings for certain keywords. It all depends on what you're aiming for. The other reason is that there won't be another update for at least another 2-3 months. So even if yours does increase you won't see it for awhile.

The thing to focus on is your actual rankings and how much traffic you're getting from various sources. Links from directores and forum signatures might bring in a small trickle of visitors which might be okay but it's best to go after a flood. How do you do that? Build good content - things that are helpful to people. Do some reasearch on "linkbait".

I can tell you from experience that forums on their own are very difficult to get links to - they're not authoritative enough most of the time to get natrual links and few will link to your main site unless they actually really like the community.