The most annoying thing for a person with multiple Gmail account is the inability to log into several accounts at the same time with the same web browser. To log in any account you have to switch in between by logging in and logging out any time you want to access any account. This can be simplified by opening all the accounts at the same time.
Below are some of the four ways you can use to log into your Gmail accounts at the same time.
1. Multiple Browsers

You can use multiple browsers to log into several accounts at the same time. You can download more browsers like opera, Firefox, safari, chrome and open one account per browser. The down fall of this method is that the more memory is drained from your computer and the tedious work of switching back and forth.
2. Master account

This is another way in which you can open your accounts at the same time. What you do ids that you create a master account in which you forward all other emails from your accounts hence reducing the need to open all the email accounts you have at the same time. To do this go to your account settings, click on forward and POP and enter the master account of your Gmail account and authorize Gmail to keep a copy of the email in the inbox. Save your changes before you exit.
3. IE Tab

This trick is from the tipster of life hacker. Similar to the first method, you will be using two browsers but the only difference is that you will be opening IE inside a Firefox through an extension known as IE tab. This will eliminate the problem of having to open several windows at the same time but will restrict you into logging into Gmail accounts at the same time. Though this method can be quite unstable sometimes and you may not find it suitable for your browser.
4. Gmail manager

This is another way to half way solve the problem because it saves you too much hassle. By using a Grease monkey script it can provide you with a drop down from which you can choose several accounts, though you can’t see them all at the same time to can choose and switch between different accounts with little ease which will save you the trouble of logging in and out of several accounts.