When I choose skills for starting dwarves, there are a few things I always keep in mind:
1. Providing food and drink
2. Mining
3. Defence
4. Constructing and furnishing a fort
5. Taking advantage of local resources
6. Focusing on particularly interesting crafts and angling for strange moods.
My load-out usually has:
- 2 Miners. They also get at least 1 point in a military skill (usually Wrestling or Archery) and often eventually become extremely powerful warriors. In most of my groups of starting seven, they're the only ones on which a strange mood is a waste.
- A Farmer/Brewer. This dwarf may also gather or (rarely) fish, but growing food and making booze are his core responsibilities. He also gets one point in a valuable craft skill for potential strange moods. If he never gets that strange mood, he'll be the chief brewer later on, as well-made drinks make a lot of dwarves very happy.
- A Farmer/Cook. Having a second dwarf who plants (when needed) means a great head start on food, drink, and (if I so desire) thread and even dye production. He also gets a interesting strange mood skill, but if the mood doesn't happen, he provides ridiculously valuable meals of Dwarven Syrup for export and local consumption.
The other three dwarves vary tremendously.
I like to have a leader. The most sociable dwarf gets this job and gets one point in Appraiser, one in Organizer, some points in social skills, one point in an interesting strange mood skill (preferably one that needs only part-time labor), and usually one point in Wrestling (for survivability). If I do have a leader, he spends a lot of time socializing at the gathering place after the first migrant wave arrives to make sure he gets and keeps more friends than anyone else.
If I want to construct a lot of stuff, then a couple of dedicated Masons are in order. If not, then one is sufficient, and that dwarf may also be a mechanic or (more rarely) a building designer. In wooded locals, a Carpenter is nice to have, but certainly not essential. Any Carpenter will also become a wood chopper, but there's no need to spend any points on Woodcutting.
Any remaining members of my original seven are usually specialized craftsdwarves hoping for strange moods and making themselves useful as fishers, gatherers, haulers, sorters, dumpers, millers, threshers, pumpers, soldiers, builders, etc. while they wait. The trade skills I focus on depend on their preferences (especially for steel, crossbows, and clear glass), on expected local resources, and on my plans for the fort.