What are some best marketing practices for startups?

SEO, email marketing and PPC

stela what is a backlink mean? what does this thing about search engine mea?

First you should try to work as Search Engine Optimization and social media connection. This is the best way to practice for your startup

What kind of startup are we talking about?

Create more backlink for your website..

The best is to have a feeder to give you money to start, like this one here...http://bit.ly/2c4jMr4

Post the howtos, presentation, videos, any testimonial you received from your beta users in your blog. Make your blog the central repository of everything related to your product.
• Schedule two dozen tweets (you could use tools like Hootsuite for scheduling) to go every hour – each covering a facet of your product – with an appropriate URL in your site

I would say it depends on the type of start up, as a hair dressing salon will have different practical ideas to focus on than an auto dealership or an online opportunity. There are common actions to take, like creating a Facebook page, making sure your immediate (local) area learns about you, via advertising (there are many on and offline ways to do that), community forums etc. If you really need to, just google the question and you may find 2,700,000 results!! Have fun working through them...!

Get a top quality affiliate product, like this one here ... https://tr.im/cash4pros ... and earn a lot of commissions promoting it as an affiliate ... I can also show you how to turn regular products into your own affiliate products and make a nice income while your affiliates bring you the sales ... start with the product I gave you here!