How can I make my website SEO friendly?

Search engines are working a way, that they are filtering out only the textual content from a website, without the html tags and css, javascript codes, plus the image alt tags. So in our slider, only the image alt tags matter (besides the text you write on the slides). The slides' background image, and every item, that is using an image has an alt tag. You should write something in there, that is connected to the other parts of your website, because search engines are putting the pages into bigger, and smaller categories. In the bigger categories there are already too many websites, so yours will be lost, that is why your goal is to get into a small category, and if someone is looking for a website like yours, they could more easily find it.
image_alt

Other parts of the website, that are looked on your website by search engines

1
Website's Title

Joomla SystemGlobal ConfigurationSite Name

WordPress SettingsGeneral

2
Meta descriptions, meta keywords

Joomla SystemGlobal ConfigurationSite Meta Description and Site Meta Keywords

WordPress in theme, probably you will have to put this into your theme's files yourself. Look for this code, probably in the header.php file:

<head>	

Write a description under it, which optimally should be between 150-160 characters, and put the keywords (~230-240 characters) there too:

<head><metaname="description"content="This is an example of a meta description."><metaname="keywords"content="Example,Nextend,Slider">	
3
SEO urls

Joomla SystemGlobal ConfigurationSearch Engine Friendly URLs

WordPress SettingsPermalinks

4
Alt tags

For your other images too, not just for the Smart Slider.

5
Links

To your website from other websites

It's important too, how "popular" your website is. If you can, then exchange links with other websites.

Things to avoid

1
Don't try to fool the users

If you have a website with a certain subject, then don't try to use popular keywords, that has nothing to do with your content, just to get people to your website, because it will have a negative effect on your ranking.

2
There are no links to a certain page

Make sure, that you have links to every page, that you have

From any page of your website the users should be able to go to every other page. If you are not using a page anymore, then delete it, if you won't need it anymore. This is for the same reason, as the previous one, that search engines doesn't like, when there are hidden content in the websites, that can mislead people.

3
Multiple copies of a page

Don't create multiple copies of a page under different URLs

If you want have your page in multiple places, then link the same page to everywhere, don't duplicate it, and use the copies.

4
Don't be impatient

It could take months to get into search engines.

Increasing factors

1

Social activity, social shares, especially with Google+

2

Website performance, have a mobile-optimized website. You can read about how you can increase your website's speed in here.