Getting entries excluding the first I'm trying to set up having the first entry pull in and then later down the page pull in the remaining posts (as I need to break the loop with other content). I'm a little unsure how to set up pulling in the 'Not firstEntry' for the second part. This is what I'm working with:
{% paginate craft.entries.section('blog').limit(1) as entriesOnPage %}
{% for entry in entriesOnPage %}
{% set firstEntry = craft.entries.section('blog').order('postDate desc').one() %}

{% if entry.id == firstEntry.id and craft.request.getPageNum() == 1 %}
//output first entry
{% endif %}
{% endfor %}

// DO OTHER STUFF

{% paginate craft.entries.section('blog').limit(12) as entriesOnPage %}
{% for entry in entriesOnPage %}

//OUTPUT 12 Entries not including the first

{% endfor %}
&quot;Measure twice, cut once&quot; goes the saying... (Kind of the opposite here, but the same principle!) - Fetch your data once, then cut it up how you like using Twig filters. In your case you can fetch the first item from an array with [0] and then slice off that same entry from the start of the same array with |slice(1) like this:
{% paginate craft.entries.section('blog').order('postDate desc').limit(13) as entriesOnPage %}

{% set firstEntry = entriesOnPage[0] %}
{% set theRest = entriesOnPage|slice(1) %}

{# ======================================================================= #}

&lt;h1&gt;{{ firstEntry.title }}&lt;/h1&gt;

{% for entry in theRest %}
    {# OUTPUT 12 Entries not including the first #}
    &lt;h2&gt;{{ entry.title }}&lt;/h2&gt;
{% endfor %}