To change the lines

Select the line, then use the tools on the toolbar. 

To change the outline colour of an object 

Select the object, then click Line Color on the toolbar.

To change the outline style of an object

Select the object, then click Line Style.

To change the fill, effect and pattern colour of an object

Select the object, then click on the Fill Color button on the toolbar. 

To add a shadow

Select the object, then click Shadow on the toolbar.