I'd like to make a more serious attempt at CF, and I thought these mage classes might be interesting. (As long as I'm going to die a lot, it might as well be with something I enjoy.) Would you please give me some advice about how they play?

It's hard for me to judge shapeshifters because I can't see what forms can do. Do forms provide much tactical variety? Are there any first shapefocuses to avoid if I want to be useful to groups?

Transmuters certainly look like they're great in groups. Are they also capable of some solo exploration, or are they dependent on more damage-oriented classes?

I expect to try joining the Heralds. Would either class obviously be more welcome?

It's hard for me to judge shapeshifters because I can't see what forms can do. Do forms provide much tactical variety? Are there any first shapefocuses to avoid if I want to be useful to groups?

The most important roles of a shapeshifter in the group are damage dealer and tank. Defense can tank to some extent with it's second tier, well with it's third tier. Utility forms can tank to some extent with their third tier and a bit with their second tier(in optimal conditions). Utility can tank to well with it's fourth tier and defense can tank extremely well with it's fourth tier. Offense doesn't tank, but it deals out nice damage. Water forms are more powerful than the other tiers, but they are limited to water rooms(seas, rivers, underwater, swamp, ponds etc.) after the first form. The early forms of utility have neat perks(such as forage or hide) that can make the early forms useful even as hero. Utility is a good choise of focus for an explorer.

Basically, you should avoid water and air as first foci, but you may choose either of them as your minor focus if you so wish. Utility major water minor could work well for a Herald explorer, allowing you to explore both on land and under water.

Transmuter's role in the group is group utility, meaning that he increases the performance of others by hasting them, slowing and softening the mob, etc. It is generally harder for a muter to kill mobs alone than for a shifter to do so.

Herald will welcome goodies and neutrals, but evils could have some problems getting in.

They can Solo explore but I STRONGLY suggest being good
**For request**
One because your groupmates will be Less likely to betray you,
Now this isn't a excuse to go elf...
You'll be semi welcome
Just make sure you slow when you need to
And haste when you need to...
And keep an eye on your groupmates
and don't be afraid not to assist
Your mana is MORE important

The shape focus most welcome at low levels is offense, later on, more defense. Avoid water focus unless you know enough water areas to rank in.

Frankly, if you are a new player, and are going heralds, transmuters are a great choice. You'll get killed a lot by ragers and rager applicants, just be invisible everywhere and always.