How fast you add links pointing towards your website will have a large effect on how well your website is ranking in Google. Building links to slowly will prevent the site from reaching its full potential as quickly as possible. Building links too fast can cause it to temporary or permanently drop in the SERP.
Google wants sites to attract links in an organical manner. Our goal is to mimic this as well as possible. Doing so will reward you with a site that ranks well with few links.
How fast you should build links depends on several different factors. The most important of these is how many links the site already has. Other factors that play an important role include how many links the site has been getting each month in the past, what industry you are, in and what type of links you are getting.
In low competition niches, it is better to play it safe and only build links slowly. It will not take very long the reach the top regardless. In more competitive industries you might have to be more aggressive and risk building links to fast. If you do not then you might never be able to catch up with the top players in the industry.
If you are building links to a new website on a new domain then you should start out very slow. You should start by building no more than one link every week. On rare occasions, you can build two links the same week. Do not point all links to the same page of the website. Spread them over a variety of pages. I recommend pointing no more than 20% of the links towards any particular page. Building links toward different pages look more natural and will allow you to rank better in the long run.
Once the website has 10 links you can increase the link building speed to 2 links a week. Once the website has 50 links you can increase to 5 links a week. I never recommend that you build links faster than that. There is no need to as long as you focus on quality links.
New website on an old domain
If you are building a new website on an old domain that already has a lot of links then you can build links faster then if you start with a new domain without any links pointing to it. I recommend that you start building links slowly. Just one or two links a week but you can increase your link building speed a lot faster. You can start building 5 links a week in as little as a month. The more links the domain has the faster you can build new links. Make sure that you build-up to the new link building speed. Do not start building a lot of links right from day one.
If you want to build links to an old site with few links then you should start building links slowly. Only build 2-3 links a month for the first two months. This shows Google that the site has started to attract new interest. After the two months have past you can start building links a lot faster. Make sure to never add more than 10% of the current link count in a week.
If you want to build links towards an already popular website that earns links organically then you can start building links fast right from the start. Do not build links at a rate faster than 10% of the total link count each week. If the website has a high number of links then you should keep the number of links you built to a maximum of 10 links a week. This is true even if this is less than 10% of the total number of links. Only build more than 10 links a week if the website in question has more than 1000 linking domains.
Try to stay consistent with your link building. You do not have to build the same amount of links each week but try to avoid building a lot of links en week and then none the next.