Give it lots of turns and drops. Be careful not to make it too intense though. For
example, if the coaster is traveling 70 mph, don't do a hairpin turn. That will up your
lateral G's so much no one will will want to ride it. A good balance between intensity and
excitement is tough.

use the tracks that are already there and see which is the best.
when building new rides use sharp banks at the end of hills and drops to save space and
keep the spped up for a enjoyabe ride

On the tutorials for building a coaster, it tells you to tilt the track when turning. But
if you keep all the turns flat the lateral G's will go way up making the exitement higher.
This may make it hard for you to get people to ride the coaster though. To solve this
problem, go to the toolbox and build your own scenario. While building your scenario it
gives you the option to set the preference of exitement for all the guests in your park
while playing your scenario. The highest preference for guests is 9+(they like exitement
ratings of 9 and above). Hope this answered your question jephjephvil.

Remember to Keep your coaster at realistic speed it helps