skills development strategy
 

Which strategies are best - focus on few like silver sword with fast and group attack styles, then choose one or two signs for spell attacks, OR develop a jack of trades character?

I'm in chapter 2 now, enemies becoming more difficult and make me think twice when developing my character's skills.

Generalist with swords, specialist with signs. There are foes you just can't fight effectively with the wrong style; OTOH signs get a lot stronger by putting more points into them, and they're generally pretty effective on all enemies. Developing your alchemy skills beyond the basics is optional -- you can get by just fine knowing only Swallow, Cat, Blizzard, and a couple of oils; however, there are some bombs that are very effective and a lot of fun, and it doesn't cost *that* much to get the skills to make them.

Develop your abilities first, skills second (e.g., bump up your strength before bumping up your Strong Steel or Strong Silver). And finally, think carefully which of the "outer ring" skills you want to take -- generally speaking the payoff is bigger when bumping up the "numbered" inner ring (e.g. Strong Silver II, III, IV and so on) than when buying the special perks (e.g. Bleeding, Bloody Rage, and so on). Some of the "outer ring" skills are really good, though, for example the ones that trip your enemies -- they'll let you go in for a coup de grace that ends the fight quickly.

Also, don't spread out too much on the signs - pick one or two and ignore the rest.

Just like PJ have said: develop abilities before skills but don't forget to developping Signs. Aard and Igni can make some battles that much less of a hassle even for a relatively low level character.