Most of the SharePoint websites I work on do not expose any of the standard SharePoint functionality. They do not use webparts and so do not require any of the SharePoint javascript functionality.
SharePoint includes files to support the client side functionality of its controls, init.js, core.js, controls.css and core.css. These files are pretty large and in the interest of increasing the speed of loading your page its best to remove them, assuming they are not being used.
So a tip for your SharePoint publishing site is to remove them, but keep them available to your authors. You can do this using the AuthoringContainer control.
<PublishingWebControls:AuthoringContainer runat="server" id="AuthoringContainer1" DisplayAudience="AuthorsOnly">
<SharePoint:CssRegistration name="<% $SPUrl:~sitecollection/Style Library/~language/Core Styles/controls.css %>" runat="server"/>
<SharePoint:ScriptLink name="init.js" runat="server"/>
<Sharepoint:CssLink runat="server"/>
</PublishingWebControls:AuthoringContainer>
By wrapping these controls with a SharePoint AuthoringContainer you can speed up the load time of your publishing site to your visitors, but keep the authoring functionality available to your site authors.
Sometimes I have also included the PlaceHolderAdditionalPageHead to ensure other unwanted js or css files are excluded.
<asp:ContentPlaceHolder id="PlaceHolderAdditionalPageHead" runat="server"/>
Another quick tip
Sometimes your custom CSS will not work well with the SharePoint field controls and so you need to fix the look and feel. This is important to make the editing experience as good as possible, ensuring the authors are happy. Personally I like to keep the default CSS specific to viewing the site and not try to have one CSS file for both viewing and authoring.
By using the SharePoint EditModePanel you can include a separate stylesheet, specifically designed to override any styles affecting the authoring look and feel. This makes the authoring experience much more usable, does not compromise your original CSS and is only included when editing a page.
<PublishingWebControls:EditModePanel runat="server">
<link type="text/css" rel="stylesheet" href="/Style Library/ARF_editing.css" />
</PublishingWebControls:EditModePanel>