To include in a table you need to add HTML tags to table:
<?php
include ('connect.php');
$sql ="SELECT * FROM tbl_venues";
$res = mysql_query ($sql) or die( mysql_error() );
if ( mysql_num_rows($res) > 0 ) {
echo '<table>';
while ( $row = mysql_fetch_assoc($res) ) {
echo '<tr>';
echo '<td> Venue Name:' . $row["venue_name"] ."</td>";
echo '<td>Venue Description:' . $row["venue_description"] ."</td>";
echo '<td>Venue Address:' . $row["venue_adress"] ."</td>";
echo '<td>Venue Type:' . $row["venue_type"] ."</td>";
echo '<td><a href="venueedit.php?venueid='.$row["venue_id"].'">Edit</a</td>';
echo '</tr>';
}
echo '</table>'
}
?>