First, right click the panel and click on 'Configure Panel' in the arrangement panel you see at the bottom 'size' if you increase the size the icons will increase in size too.
To move the applet, if you move your mouse over the applet to the right or left you'll see a little arrow, right click on the arrow and you see the pop up asking you what to do, there you can choose to move the applet.
While this works perfectly on the application icons in the panel, it has no effect on the applet icons, or an the icons that represent the various desktops. I cannot move or resize ether of the last type, which by the way do not have an arrow right or left of the applet icon..
The size of the icons for the pager application (desktops) is dependent on whether it is configured to use 1, 2 or 3 rows. The more rows the smaller the individual desktop is displayed. The quicklauncher also uses small icons by design, to fit more launchers in a given space.

Note on the left are application launchers added directly to the panel. Next are my 20 desktops, followed by three more panel launchers, then the space saving quicklauncher icons. To the left of the desktops, a vertical bar will appear if the mouse cursor is hovered there, and a right click will reveal a menu. One of the options is
Launch Pager, which can also be accessed by right clicking on any individual desktop icon, which shows the desktops in a larger view, with indications of what applications are open on each desktop. I've split the screen shot for compactness.

This left half of the pager represents the top row of desktops on the panel, with my
Pidgin Buddy List open on desktop 1,
Skype open on desktop 7, a
Konqueror window open on the bottom half of desktop 8, and
Firefox open, full page, on desktop 10.

The right half of the pager represents the bottom row of desktops on the panel, showing
KDiskFree and a
Konqueror window open on desktop 16,
KDiskFree covering the top half and
Konqueror the bottom half of the desktop. Desktop 20 has a maximized
root terminal covering the entire desktop.
To gain space, I've added a second narrower panel to hold a
Run Command box, on the left end, the
Task Bar, in the center, and a
Kdict dictionary box, on the right end. Again, the view is split for compactness.


Note that everything is placed on the panels as I feel they are most efficient for how I work. Each applet has it's own characteristics built in, some being more configurable than others, but their location is totally up to the user. If you have a problem with a specific applet, supply the specific details for that applet. Don't lump all applets together in broad statements, as each has to be handled in it own way.