1. In the new releases since the one on the 1st April, surface trees matter significantly less; you can always dig down to the caverns and there'll be underground trees there, you can dig out and muddy further artificial tree farms, and there's often an unlimited source of water underground. For clear glass projects, the main concern, above all others, is magma availability; clear glass, if you don't have magma, takes 3 wood to make (1 wood for pearlash and 2 for charcoal to do the potash -> pearlash reaction and the sand/pearlash -> clear glass reaction). Embark on a volcano, or set your worldgen parameters so the magma sea is more readily available by reducing the number of cavern layers to 1, if not both.
2. Having a skilled grower early is always very useful. A doctor is also useful, though if you're careful you can prevent any injuries until you've got time to arrange minor "accidents" to hurt people so a doctor can train. A skilled carpenter is also nice to produce quality beds for early happy thoughts from decent bedrooms, and a skilled mason similarly helps make a nice early dining room.
3. Whether or not you bring an anvil matters far less now than it did in 40d; in 40d, you got ~1400 points and anvils cost 1000, while now you get ~1300 but anvils cost 100. Food and drink are top priority; you should have ~40 food and 80 drink, minimum. That'll tide you over until winter, even with feeding migrants, and by that time you should be able to have farms and stills up and producing. Other than that, raw materials are nice (especially wood), as are livestock (especially dogs), and tools.
4. Playstyles vary drastically from person to person. Myself, I always start by digging out a large space for a stockpile while my carpenter makes beds, then make a few bedrooms, then move everything from the wagon into the stockpile space. Once that's done, farms get dug out and irrigated, temporary workshops are set up for masonry and mechanics while a moat is dug and a drawbridge set up, permanent workshops are arranged for food and booze, and then the early stages are more-or-less done. For farmland, I usually have too much; you can feed a sizable fort on 25 tiles producing plump helmets year-round, but I often make 4 farm plots that take a variety of seeds that are each ~33 tiles.
5. Defense is another thing that varies dramatically with playstyle. I always get a drawbridge or two over a moat or two (a habit learned when playing with the Orc mod in 40d) and, if needed, simply seal the gates and wait out sieges. Otherwise, forcing enemies down a well-trapped corridor or into a more complicated deathtrap are effective methods, as are methods to seperate enemies into smaller groups that dwarves then mob, as are, later in the game when you've got better soldiers, simply sending your heroes out to take down the enemy.
Hunters should not be butchers. Hunting is a higher-priority task than butchering, so a hunter/butcher will almost always ignore the corpses to go hunt more. Butchery is an important enough task that your butcher(s) should do nothing but; nothing is worse than designating a kitten for slaughter, only to have it adopt someone before your butcher gets to it because the butcher was busy cooking, except perhaps a dragon's corpse rotting because of the same reason.