The most basic function of adjectives is to describe a noun, but they can also form a comparison. When they do, they fall into one of two categories: "Comparative" adjectives compare one noun with one or more others. "Superlatives" compare nouns with all others. (Ordinary adjectives are technically called "positive," so the progression is: positive, comparative, superlative.) An example in English of all three forms is "good, better, best." A song you like might be "good." It might be "better" than other songs. Or it might even be "the best" song. Two other English examples are "cool, cooler, coolest" and "interesting, more interesting, most interesting."
From these three examples we see that English has three different ways of making comparative and superlative adjectives: different words, as in good/better/best (these are technically called supletive forms), with suffixes and with the words "more" and "most." The good news is that Hebrew, unlike English, has only one way of making comparatives and superlatives, and it corresponds to the "more"/"most" scheme. But we should hardly be surprised that Hebrew has its own quirks.
The word 'yoter' / יותר (more) is the basic comparative word. So starting with 'tov' / טוב (good), we get 'yoter tov' / טוב יותר (better). But we also get 'tov yoter'. They're both grammatical, and they mean exactly the same thing. The only difference is that 'tov yoter' is a little fancier ('yoter fansee', we might slangily say, or 'hadur yoter' in more formal speech).
Superlatives in Hebrew are also formed with the word 'yoter', this time with the prefix b'. So "the best" in Hebrew is 'hatov beyoter' / הטוב ביותר, literally "the good in-more." There's no word swapping allowed in the superlative, so b'yoter hatov' isn't an option.
Hebrew does offer another way of forming the superlative, though. The word 'hachi'/ הכי, like 'b'yoter', means "most." So equivalent to 'hatov b'yoter', we have 'hachi tov' (also best), and again no order changes are allowed. So to pick a sentence completely at random, the Hebrew translation of "Hebrew is the most interesting language" is '3ivrit hi hasafa hachi me3aniyenet'/ עברית היא השפה הכי מעניינת or '3ivrit hi hasafa hame3aniyenet beyoter' / עברית היא השפה המעניינת ביותר. Oddly, sometimes when the superlative is modified - for example, by the redundant 'sheyesh'/ שיש (that there is) - the 'hakhi' option works much better: '3ivrit hi hasafa hakhi me3aniyenet sheyesh/ עברית היא השפה הכי מעניינת שיש, not usually ...'hame3aniyenet beyoter sheyesh'.
The word "than" in Hebrew is simply the word "from," usually the prefix 'mi'/ מ. So - again picking a sentence at random - "the grammar is more interesting than the content" is either 'hadiqduq yoter me3aniyen mehatokhen'/ הדקדוק הוא יותר מעניין מהתוכן or 'hadiqduq me3aniyen yoter mehatokhen'. But in fact there's a third option, too, because once the 'mem' of comparison gets into the act, the comparative word 'yoter' becomes optional. So we also have the pithy 'hadiqduq me3aniyen mehatokhen'. And as it happens, that's the most common option. It's as if in English we could say "interesting than" instead of "more interesting than."
Adverbs - which are essentially the same as adjectives in Hebrew - work almost the same way. "Sarah runs quickly" is 'sara ratsa maher'. (Notice that the adverb here stays masculine). "Sarah runs faster than Moshe" is 'sara ratsa yoter maher mimoshe', though the word 'yoter' is once again optional and generally omitted. "Sarah runs the fastest" is 'sara ratsa hakhi maher'.
Unfortunately, 'sara ratsa maher beyoter' is not superlative. It just means "Sarah runs really, really fast," not Sarah runs the fastest. The word 'beyoter' here is augmentative. In fact, if we leave off the 'ha'- (the), 'beyoter' can have this augmentative role with adjectives, too. 'me3aniyen beyoter' means "very interesting," while 'hame3aniyen beyoter' means "the most interesting."
Closely related to comparatives and superlatives are the phrases "too" and "too much." Both of these constructions in Hebrew are built around comparison to "enough": 'yoter midai'/ יותר מידי , literally "more than enough." So "too fast" is 'yoter midai maher', as if to say, "more than fast enough." And "too much grammar" (clearly a ridiculous concept) is 'yoter midai diqduq'.
There's more, of course - there always is - but now you know the basics, at least more or less.
הספינה כבדה יותר מהמכונית. הרכבת ארוכה יותר מהמטוס. הבניין גבוה יותר מהמסעדה. יש לה השיער הכי קצר. מזג האוויר היום הוא הגרוע ביותר השנה.
למה אתה אוכל יותר מדי שום?
למה אתה אוכל יותר מדי שום?