You can access an element's parent node and its child nodes.

html
<div id="parent">
<p>Child 1</p>
<p>Child 2</p>
</div>

javascript
const parentElement = document.getElementById('parent');

// Access the parent node
const parentNode = parentElement.parentNode;

// Access child nodes (including text nodes)
const childNodes = parentElement.childNodes;

// Access only the element child nodes
const children = parentElement.children;

You can access an element's previous and next sibling nodes.

html
<div id="parent">
<p>First</p>
<p>Middle</p>
<p>Last</p>
</div>

javascript
const middleElement = document.getElementById('parent').children[1];

// Access previous sibling node
const previousSibling = middleElement.previousSibling;

// Access next sibling node
const nextSibling = middleElement.nextSibling;

You can find elements relative to another element using `nextElementSibling`, `previousElementSibling`, and `parentElement`.

html
<div id="parent">
<p>First</p>
<p>Middle</p>
<p>Last</p>
</div>

javascript
const middleElement = document.getElementById('parent').children[1];

// Access previous element sibling
const previousElement = middleElement.previousElementSibling;

// Access next element sibling
const nextElement = middleElement.nextElementSibling;

// Access parent element
const parentElement = middleElement.parentElement;

You can use `querySelector` and `querySelectorAll` methods to find elements using CSS selectors.

html
<ul>
<li class="item">Item 1</li>
<li class="item">Item 2</li>
<li class="item">Item 3</li>
</ul>

javascript
// Using querySelector
const firstItem = document.querySelector('li.item');

// Using querySelectorAll (returns a NodeList)
const allItems = document.querySelectorAll('li.item');