How to securely manage user accounts?

Hi, I have a website idea that would involve member registrations and an account login for (the usual to become a member of a site).
What I am wondering is:
(1) How do I securely log someone in?
(2) How do I display information specific to someone's account? (ex. every user has some amount of points, how would I display the right value for the right person)

I'm assuming this involves MySQL databases, which isn't a problem. I just want to to be secure and professional, help?

 

To securely log someone in use sessions and you can encrypt their passwords. A quick Google could help you get more information on that. To display information from someones account use something like this:

$sql = "select * from accounts where name='$_SESSION[username]' and pass='$_SESSION[password]'";
$result = mysql_query ($sql);
while ($row = mysql_fetch_array($result))
{
         $Points = $row["points"];
         echo "You have $Points points!";
}

Code (markup):

 

One of the basic tips is :

Don't store the passwords in their real form. Encrypt it using, eg: md5()

This applies for passwords in cookies / mysql database.

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Secure is a broad sense. It relies on what your thret model is. For simple sites, just don 't display them and make sure you do not have sql injection errors.