How to display multiple fields in one line in drupal
As mentioned in the comments, you need to use CSS to achieve this. Drupal makes it really easy by wrapping the elements nicely with divs and relevant classes. For example, if you are creating a new issue in Drupal.org, the form provides http://drupal.org/project/issues/linkedin?categories=All this kind of structure.

Using an inspector tool, you can find the target divs and apply a CSS in this way to your theme:

.views-exposed-form .views-exposed-widget {
    float: left;
    padding: 0.5em 1em 0 0;
}


Thats it. Don't forget to clear your cache to see the changes!