The one rule
Punctuation is never joined. Finish the last letter's exit stroke, lift the pen, place the mark, and start the next word with its own entry stroke. Every other rule is about where the mark sits: periods and commas on the baseline, apostrophes and quotation marks at the top line, hyphens and dashes at the midline, question marks and exclamation marks spanning the full height with their dot on the baseline.
Apostrophes inside words
The awkward case is an apostrophe inside a joined word, as in don't or o'clock. Write the letters before the apostrophe, lift, place the apostrophe at the top line, then write the remaining letters starting from the baseline with a normal entry stroke. The gap under the apostrophe is expected; closing it produces a cramped letter.
Capitals after punctuation
A period is followed by a space and a capital, which usually stands alone anyway; if the capital is one that joins (A, C, E, J, K, L, M, N, R, U, Y, Z) the word continues from its exit stroke as normal. After a comma, the next lowercase word starts with its entry stroke from the baseline; the comma does not shorten it.
Quotation marks and dashes
Opening quotation marks go before the entry stroke of the first word and closing marks after the exit stroke of the last, both at the top line. A hyphen between two joined parts, as in well-known, breaks the join: finish "well", lift, draw the hyphen at the midline, and start "known" with a fresh entry stroke. Dashes are longer hyphens and take a space on either side in most school models.
Where the practice pays off
Addresses, dates and dialogue are where punctuation piles up. The copywork sheets with quoted speech, and the days-and-months sheet that mixes commas and capitals, give the pen lift its rhythm.
Practising
Sentence copywork is the best practice for punctuation because every line has a period and most have a comma or an apostrophe. The sentences worksheets pack includes a punctuation-heavy set.