Landing page optimization?

Question

Search Engine Optimization

Piece torn from several sites

<meta name="ROBOTS" content="ALL" />
    <meta name="robots" content="index, follow, noodp">
    <meta name="googlebot" content="index, follow">
    <meta name="keywords" lang="en" content="egaming bets, esports bets, esports betting" />
    <meta name="description" lang="en" content="Welcome to Egaming Bets, a new online bookmaker platform providing exciting eSports betting odds for Dota, League of Legends, StarCraft 2, WoT and more" />    <meta property="fb:app_id" content="105386699540688">
    <meta property="og:site" content="Steam">
    <meta property="og:description" content="Трем героям предстоит совершить полное опасностей путешествие в фантастическом сказочном мире. Решайте задачки, наслаждайтесь графикой и не забудьте про друзей!">
    <link rel="canonical" href="http://store.steampowered.com/app/35720/Trine_2_Complete_Story/">
    <link rel="image_src" href="http://cdn.akamai.steamstatic.com/steam/apps/35720/header.jpg?t=1477041084">
    <meta property="og:image" content="http://cdn.akamai.steamstatic.com/steam/apps/35720/header.jpg?t=1477041084">

I do SEO optimization of the landing page.
1 - is there any difference to capitalize or small the name of the meta tag?
2 - is it better to write the ROBOTS meta tag, is the first tag or the second better? What to add for google roofer?
3 - is it necessary to specify the language in the lang="en" meta tags?
4 - what give meta

<link rel="canonical"
 <link rel="image_src"

And are there any other links that should be added to the page?
5 - Is it still possible to somehow optimize the SEO of the page? How?

Answer 1

1. No difference
2. It is not necessary to prescribe in principle
3. When the site supports multilingualism - yes.
4. Depending on which meta. Roughly speaking, they contain information needed primarily by search engines
5. Canonical points to the main page preferred for indexing (when you have similar / identical pages and you want Google to treat them as a whole, let's say, and did not recognize the pages as duplicates). Image src is, roughly speaking, a type of link in which the transition is carried out by clicking on the image
6. For full-fledged SEO optimization, a very large amount of work needs to be done.
But, if you start with something, then this is with technical on-page optimization. If you have a minimal understanding of the parameters [at least] of the internal optimization of the site, I would advise you to download Netpeak Spider (14-day trial) and check the site for errors (first of all - "red", then already "yellow"), which can then be turned by hand. If there is a risk of aggravating the situation, rather than improving, it is better to contact a specialist.

Answer 2

keywords has not been necessary to use for 6 years already, it is of no use. it is better to set the settings for the robot in robots.txt - its absence is bad.