At McKnittey, our core business is fingering and lace weight projects. While these size yarns may be intimidating at first, these yarns allow you more bang for the buck. You get more yard per skein and can accomplish more knitting from one skein.
For instance, Dream in Color Classy, a worsted weight yarn we love (Yummo!) knits up at 4-4.5 stitches per inch while Dream in Color Smooshy, a fingering weight yarn, knits up at 7.5 - 9 stitches per inch. Classy has 250 yards per 100g skein while Smooshy has 450 yards.
Fingering weight yarns also make for lighter weight garments with more drape. When doing lacework, eyelets created with a smaller yarns like fingering and lace make logically are smaller and more delicate. Fingering is the most common weight used for socks because you can create a thinner, more pliable fabric that you can actually get a shoe over.
Fingering is also ideal for infant garment for the same reasons mentioned above.
To me, the trick with managing the smaller yarns is to use good needles (I use Chiao Goo or Kollage) and to start with lighter color yarns with little halo. Darker color yarns can be difficult to see the stitches and a fuzzy yarn with a halo can also obscure stitches. I find good lighting is a must. I own two Stella lights and an Ott light.
I would love to hear other tricks for knitting with smaller yarns.