You just need to use the XML function

<earnings_index_index translate="label">
    <update handle="customer_account"/>
    <reference name="my.account.wrapper">
        <block type="earnings/earnings" name="earnings" />
    </reference>
</earnings_index_index>

You just need to use the XML function

<earnings_index_index translate="label">
    <update handle="customer_account"/>
    <reference name="my.account.wrapper">
        <block type="core/template" name="earnings" template="earnings/earnings.phtml" />
    </reference>
</earnings_index_index>

To change the default title within your controller you'll need to place

$this->getLayout()->getBlock('head')->setTitle($this->__('Title here'));

Withing your loadLayout() and renderLayout() calls, such as:

$this->loadLayout()
$this->getLayout()->getBlock('head')->setTitle($this->__('Title here'));
$this->renderLayout();