I have been trying to make my websites looks and when ever i make a top banner that spreads across the page, it looks ugly and childish. Can someone tell me how to make a nice banner like daniweb which is appealing.
I thinks its going to be hard to tell you how to make something look appealing. There are a lot of factors..such as color, size, fonts, images, layout, etc..
How about if you visit some of the sites that you find the top banner to look nice, then just view the source code (right click on the browser, view source), so you can get a better idea how the layout was designed and how the use of styles makes the banner look pleasing.
is it even possible to view other websites css style sheets
When you look at the source code, you can see the reference to the stylesheet. For example, if the reference is "/styles/style.css", then you could get to it by typing in the URL, http://www.domain.com/styles/style.css. Some browsers, such as Google Chrome, will automatically create the hyperlinks for you when looking at the source code so you just click on the reference and the browser opens up a new tab or window with the results.
While I am not encouranging you to copy other people's code, you can at least take a look when trying to determine how things work.