How can do i do a tune-up in 2000 chevy blazer ls

no tmuch to due, replace spark plugs, air filter. the fuel filter is the hardest, its under the vehicle. if you plan on replacing it, becarful, you will get gas running down your arms into the your arm pits. (this is burn) so becarful during this replacement.
you'll need "line" wrench to replace this filter, do not try removing the filter without a line wrench, by using a regual wrench it might be very tight to remove and a regual wrench will round off the nut where a "line" wrench will not. If you round off the fuel line nut, stop and tow it to your nearest dealership. they will have to replace the WHOLE fuel line.