Magento – How to create observer to change order status after it was created

Magento has a default authorize which sets the state as processing.

You will have to edit/override the below file: code/core/Mage/Sales/Model/Order/Payment.php

protected function _authorize($isOnline, $amount)
{
    // update totals
    $amount = $this->_formatAmount($amount, true);
    $this->setBaseAmountAuthorized($amount);

    // do authorization
    $order  = $this->getOrder();
    $state  = Mage_Sales_Model_Order::STATE_PROCESSING;
    $status = true;

Change the state to new or whatever you want to set when authorizing any payment from payment gateway.

I can give you an example how to add additional status to existed payment method.

Magento by default in system / configuration has such as 'New Order Status'.

Let's look at SavedCC:

Now we change system.xml file.

Original:

                    <order_status translate="label">
                        <label>New Order Status</label>
                        <frontend_type>select</frontend_type>
                        <source_model>adminhtml/system_config_source_order_status_new</source_model>
                        <sort_order>2</sort_order>
                        <show_in_default>1</show_in_default>
                        <show_in_website>1</show_in_website>
                        <show_in_store>0</show_in_store>
                    </order_status>

You need to replace

<source_model>adminhtml/system_config_source_order_status_new</source_model>

with:

<source_model>adminhtml/system_config_source_order_status_newprocessing</source_model>

And you will get: