If you are a top blogger in your niche or field you should be having thousands of RSS subscribers or feed readers. If you get daily good traffic via Google like search engines this not means you have so many subscribers. Before giving you any tips for getting more subscribers one thing I have to make clear getting so many subscribers is not easy, not easy for anyone.
(1) If you do not have so many subscribers then if you observe you will find your blog should be having higher bounce rate over 80% or similar. So try to lower your bounce rate because if a reader will not find a niche he will not find useful stuff for him and he will not subscribe to your RSS feed.
(2) Readers subscribe you and unsubscribe you
Today 10 readers subscribed your blog and tomorrow 8 of them unsubscribed after reading your next post. This is very common problem, today’s readers is very clever he can easily make a decision about your blog and its quality and niche. A reader liked your one post and subscribed your blog but next day when he receive others post from your blog that he does not liked he will unsubscribe you.
(3) Give free eBook on RSS subscription
If you are a blogger, means you are a writer so you can write an eBook in PDF format and offer it to your reader if they subscribe your RSS feed. This is not a free solution for this you have to use Aweber of Aweber like email marketing service. I have observed MakeUseOf.co had only 26000 subscribers from long times but when it started giving free eBook on RSS subscription it reached to 290000 subscribers and still growing.
(4) Post Free Giveaway
This is also not a free idea but successful. Suppose a product or program is not free but you can give it your readers free of cost, you do not have to give all readers but one lucky winner. MakeUseof.com is using this trick.
(5) Give Discount Coupons
If a program, product or service if for $40 and you can give a discount coupon of 25%. You will get some money and some of subscribers. MakeUseof.com is using this trick.
(6) Wait for Subscribers
This is my experience as your blog grow old your RSS subscriber number will grow.
(7) Request your readers to subscribe
This is very good idea to request your readers to subscribe to your posts at the end of blog post, ask them ‘if you liked this article please subscribe to RSS feed (With link) to get daily updates’, this is very effective.
(8) Write for readers and not for search engines
This is most useful idea it will save your thousands of dollars, so write quality contents, interesting things and useful.
(9) Install WP-Greet Box plugin
You can download this plugin here; if a visitor is coming from Google this plugin will welcome that reader as Hello Googler welcome to my blog and requesting him to subscribe your blog.
(10) Provide your readers more subscribing options
Put a subscription box at the end of blog post. Place a subscription box sidebar on top or you can put a subscription box on header. You can place RSS button also.
You can be more creative with your blog for RSS subscribers.