I have a 1998 kawasaki kx 60 and my suspension is very soft and it make the bike low how do i make it stiff

If its a late 90's 60, I'm guessing it's seena little use.  You probably need to freshen everything up.  If you want to spend the money then have the suspension rebuilt by a reputable shop and you'll be very happy.  If you would like to learn more and start to do it yourself, then there are soe great resources for learning about it online.  Try a search in google for the year bike and fork rebuild.  Find out how complex it is and then you can decided if you want to order teh oil, seals, etc. and do it yourself.  The year bike you have ought to be fairly simple.  I would recommend that you look on the TW site for the way to set your sag properly, and do that first.  You'll also want to figure out real quick if you need larger springs for your machine.  If it really sits that low, you may be overloading the suspension, and if you don't get the right springs in there it will always be under performing.  Factory Connection is my favorite, and if you call them up they will walk you thourgh analyzing your problems and selecting teh best fix.  They can recommend settings and springs for your weight and riding style as well, and are pretty nice guys all around.  Google them and you can find their number. 

http://www.factoryconnection.com/index2.htm is their webste.  Good luck.