PATTERN CONTENT, GAUGE and SUBSTITUTIONS (not pattern reading)
1. Materials needed
(i) hook size (ii) Yarn information:
a. suggested yarn (color/brand)
b. weight (sport, worsted, bulky, etc.) sometimes accompanied by
universal no. 1, 2, 3, 4.
c. ounces or yardage needed to complete project
d. gauge (amount of stitches/rows per inch)
2. Stitches used (ch, sl st, sc, hdc, dc, trc, etc. or special stitches)
3. Stitch sequence (how the stitches are put together to form the piece)
GAUGE (and SUBSTITUTION)
1. When and why gauge is important / finished measurements, sizing and fit:
a. When FIT doesn't matter: If the project is a blanket, scarf, stuffed animal, purse/tote - gauge is not crucially important. If a baby blanket's measurement is quoted in a pattern as 24" X 24", and your finished piece is 25"X25" or 23"X23" that is immaterial to the item's function. Thus, if FIT doesn't matter, gauge doesn't matter. Go ahead and use the recommended hook and yarn, or substitute a like-weight yarn, and the finished size will be fine.
b. When FIT matters (sweater/hat/socks, etc.) correct gauge is crucial. We naturally assume that, by using the stated hook size and exact recommended brand/weight yarn, the the item will be identical to the project's specified size/fit. Generally, this WILL be the case. However, by taking the time to work up a gauge swatch, the possibility of sizing errors (and disappointment in a finished project) is eliminated.
2. Reasons for differing gauge (too small, too big)
a. Naturally crocheting tightly or loosely; correcting gauge with hook substitution:
Patterns intended to fit generally list the gauge and suggest working up a gauge swatch, which is a small sample of the stitches worked over a few repeats. For instance, an item worked in double crochet gives the gauge: 8 rows and 8 stitches = 2 inches. Using the suggested hook and suggested weight/brand yarn, you would crochet 8 double crochet stitches for 8 rows, then measure your swatch with a ruler, from side to side and top to bottom. If your result is a perfect square 2"X2", your gauge is correct, and your item will fit as specified. If your gauge swatch measures 1.5"X1.5", you should try a larger hook and work another swatch. Chances are, this combination will give you perfect gauge. Conversely, if your initial gauge swatch is 4.5"X4.5", you should try a smaller hook to reach gauge. Thus, talking the time to make gauge swatch will let you know whether or not your item will fit before you start the actual project.
b. Yarn substitution (from that suggested in pattern):
When substituting yarns, look to the yarn information, which can be found on its label, on the pattern, or on the internet if not given in the pattern. Look to substitute a like-weight yarn. Unfortunately, not all yarn properties are even across the board. For instance, a perfect example of this is worsted weight Red Heart Supersaver vs. Caron's Simply Soft. The label for each of these yarns states "worsted weight" with a universal number "4". However, Caron's Simply Soft is visibly thinner, and a bit "more stretchy" thus, the same hook, same stitches, and same amount of rows, will give a slightly smaller result than RHSS, simply due to the different qualities of each yarn--even tho both are listed as being the same. Another difference is that the RHSS swatch will be stiffer while the Caron's SS swatch will have a silky drape. The same "fix" applies here...make a gauge swatch, if it is too small, try another with a larger hook--conversely, if it is too large, try again with a smaller hook--in this instance, the key to getting the right gauge for the pattern is hook size.
OF MOST IMPORTANCE: When switching yarns you must "get the same" stitches per inch, which is generally specified on a yarn's label, or in the internet description, and is a good starting point for finding like-weight substitutions.
Lastly, make sure you have ENOUGH yards/ounces of the substituted yarn. The yardage/ounces can be found on the label. This is especially important if the suggested yarn/brand comes in skeins, and the yarn you wish to substitute comes in balls or hanks. Get enough YARDS to complete your project.