Getting advertisers for my newspaper?

how to approach advertisers. ??

There is no easy answer to this question or rather there is... hard work and sweat.
Specifically the easy part... you should have a little media package made up containing a couple of recent issues, a price list for advertising (which would also include discounts for long term advertising {say something like for ever 5 advertisment you get one free), a readership target profile, a brief profile of your newspaper (what it stands for) and a circulation report (how many papers you sell or send to subscribers and at what interval).
The relatively easy part.... Think of themes/topics that work with your niche, then think about which companies/advertisers would benifit from appearing along with the topic. Think about what type of interviews you could get from business owners regarding the topic.
The hard part... Go to companies in your area/region that fit your target group and talk to them, leave them the media pack and call them back and go by again and again. If you haven't worn out a pair of shoes then you haven't tried hard enough.
Extra tip could be extremely hard or easy... Actually getting them to pay. Make sure nothing is left to word of mouth always give the advertiser an offer which they SIGN.

Write about the profile of your readership and contents. Write to key advertisers who can make use of this readership and contents as a draw for their products.