You shouldn't need to adjust the front derailleur when you change the cable (assuming that it is set up correctly with the old cable) Definitely worth getting a good pair of cable cutters, and some cable crimps.If you buy Teflon lined cables they don't need lubing for other cables chop the inner cable close to the nipple that doesn't fit your bike, then remove the inner cable and run it through a little grease held in your hand (although my preference is to use a little engine oil as I have loads of it and I believe it keeps things smoother) before replacing the cable into the inner. Most cycles have split outers in short lengths - so make sure you use the original outers as templates and cut your lengths the same. At the end of each piece of outer, you should place a ferrule to stop the outer splaying. You may be able to remove the ferrules from the existing outers. When you cut your outers, use the old inner cable and thread it in to the outer to support the area of outer you are cutting so that the outer doesn't deform. I always use a sharp round pointed object and insert it into the cut end of the outer to ensure it is completely round.
The above may not be necessary just yet - but for the cost of a cable outer I would always replace both together.