Lots of ways!
Using circ's or dpn's:
you can knit a flat (disk) circ by starting with X (4 0r 8 stitches) and every time you double the rounds, double the stitches
--that is, cast on 4, R1: K4, R2 (number of rounds has doubled--so double # of stitches) K1,YO, (4 times/8 stitches.
R4: (once again, you've doubled (from 2 to 4) so increase (double stitches, K1, Yo, (8 times!/16 stitches
R 5, Knit
R8 (double from 4!--so double stitch count--K1, Yo, (16 times/32 stitches)
proceed, increasing again on R16, R32, R64, etc
(if you start with 8 you'll have the same numbers of stitches, but they will be on different row numbers)
OR follow this pattern:
cast on 8,
R2: K1, Yo (8 times) (16 stitches
R4: K2, Yo (8 times)(24 stitches)
R6, K3, Yo (8 times--32 stitches)
(continue in like manner, 8 evenly spaced increases every other round)
But you can also knit a disk flat on straight needles
cast on 24,
r1: K20, wrap and turn
R2: Knit every stitch
R3: Knit 16, wrao and turn
R4: knit every stitch
R5: Knit 12, wrap and turn
R6: knit every stitch
R8 Knit 8, wrap and turn
R9: Knit 4 wrap and turn
R11: Knit across row, picking up all the wraps as you go.
R12, Knit across row.
Start again with r1: repeat until you have knit enough wedges to make a disk bind off, and sew cast off edge to cast on edge!
but you can also knit rounds (tubes)
and again there are several ways..
the classic knit in round (on DPN's, or circs (2 circ's or 1)
you can also knit in round (tube ) by casting on an even number and work on straight needles!
*K1, bring yarn forward as if to purl, slip 1, bring yarn to back as to knit.
repeat this pattern across row, and repeat for every row. (simple double knitting)
depending on your cast on/set up this will be a closed or open ended tube.