Students need to learn six categories of spelling rules. Most apply to Anglo-Saxon words and occur because of the short vowel sounds. Many teachers talk about “rules” that are actually not orthographic rules. For example, “When two vowels go walking, the first does the talking” – is not actually a “rule”. Smelt (1976) found that this statement is only true 37% of the time; it works for ai, oa, ay, and ee but not for oo, oy, ew, au, and aw.

Teach these rules when students are ready for them:

1. Silent e rule (VCE rule)
1. Silent e on the end of a word signals that the single vowel immediately preceding a single consonant is long as in cube and vote (i.e., the silent e makes the vowel “say” its name; sometimes this rule is called the “magic e rule”).
2. Silent e makes y say /i/ as in type and style.

A preceding single vowel may or may not be long before –ve. The vowels in gave, five, and drove are long; the vowels in have, give, and love are short.

2. Doubling rule (-ff, -ll, -ss, -zz)

Double final f, l, s, and sometimes z immediately following a single vowel in a one-syllable word, as in staff, bluff, tell, still, grass, bliss, buzz, and jazz. (Common exceptions are pal, gal, if, clef, gas, this, us, thus, yes, bus, plus, and quiz. [Although quiz contains two vowel letters, q is always followed by u in English words so only i is considered a vowel in quiz.])

3. Soft c and g rule

The letters c and g have a “soft” sound when they appear directly before e, i, and y.

1. The letter c has the /s/ sound before e, i, and y, as in cent, city, and cycle.
2. The letter g has the /j/ sound before e, i, and y, as in gentle, ginger; and gym. (Exceptions to the soft g rule do not present spelling problems because in such exceptions, g has its “hard” sound, as in get, give, buggy, and bigger.)
4. The –ck, -tch, -dge rule
1. Use –ck to spell the /k/ sound immediately after one short vowel at the end of a one-syllable word, as in back, clock, duck, stick, and deck.
2. Use –tch to spell the /ch/ sound immediately after one short vowel at the end of a one-syllable word, as in batch, itch, stretch, Dutch, and notch.
3. Use –dge to spell the /j/ sound immediately after one short vowel at the end of a one-syllable word, as in badge, ledge, bridge, dodge, and fudge.
5. Adding suffixes to Anglo-Saxon base words
1. Drop final –e rule: When a base word ends in a final e, drop the e before adding a suffix starting with a vowel (e.g., take, taking; fine,finer; stone, stony).

Double-letter rule: In a one-syllable word with one short vowel (a closed syllable) ending in one consonant, double the final consonant before a suffix starting with a vowel (e.g., -ed, -er; -ing, -y, -ish). Do not double the final consonant before a suffix starting with a consonant (e.g., -ful, -ness, -ly, -ment, -ness). Examples: fit, fitted, fitful; sad, saddest, sadly; red, redder; redness; and ship, shipping, shipment.

2. Change final y to i rule: When a base word ends in y, change the y to i before adding a suffix, unless the y is preceded by a vowel or unless the suffix begins with i (-ing, -ish, -ist). Examples: cry, cried, crying; copy, copies, copyist; and play, play; playing.
6. Plural –s and –es rule
1. Most nouns become plural (to indicate more than one) by adding –s e.g., hat, hats; pig, pigs; girl, girls; hut, huts).
2. Nouns ending in –s, -x, -z, -ch, and –sh add –es for the plural. Students can hear the additional syllable formed by the –es ending (e.g., glass, glasses; box, boxes; waltz, waltzes; lunch, lunches; wish, wishes).
3. Nouns ending in y form the plural according to the regular suffix addition rule. That is, change the final y to i and add –es, as in fly, flies. If the letter y follows a vowel, then keep the y and add –s, as in boy, boys.
4. Exceptions exist for some nouns ending in f or fe; these change to –ves as in shelf, shelves; leaf, leaves; knife, knives.
5. Nouns ending in o sometimes add –s and sometimes add –es (e.g., piano, pianos; tomato, tomatoes). Students should check their dictionaries to be sure.
6. Some plurals are completely irregular and must be learned (e.g., foot, feet; mouse, mice; man, men; woman, women; goose, geese; moose, moose; pants, pants; deer; deer). Most of them can be spelled correctly by using sound sequences for clues.

Just as when learning a new pattern, children should have ample opportunities to read and spell numerous words fitting each rule. The teacher should make the rules concrete for students. The teacher may state the rules but also must work with students so that they practice and think about each rule. Working on the board or with transparencies is useful. For example, when discussing changing y to i, the teacher can easily erase and change the y to i, if the conditions permit (e.g., try, tried, trying).

The above rules have been taken from:
Unlocking Literacy – Effective Decoding & Spelling Instruction by Marcia K Henry Paul H Brookes Publishing Co, Maryland, 2003. pp 75-79.