Rise of the Salamanders

Managed to get a good few games of 6th ed. in with my fledgling Salamanders with varying degrees of success (well, no success). I've drawn and lost against Grey Knights, lost against Tau and been slaughtered by Dark Eldar. My current list is as follows (1500 pts):

Vulkan

Tactical squad w/ flamer and multi-melta

Tactical squad w/ meltagun and multi-melta

Terminator assault squad w/ thunder hammers and storm shields

Assault squad w/ thunder hammer and storm shield

Stormtalon w/ twin linked assault cannons and twin linked lascannons

Allies

Farseer w/ spirit stones, warding, witnessing, doom, guide, singing spear

Pathfinders

Dark reapers

This is the list is lost with yesterday against Tau, although I was almost on the relic; if it had gone to another turn I could have snatched a victory. In a 2000pt game I'd add a rhino for one of the tactical squads and a land raider redeemer for the terminators and Vulcan. In the last 2000pt game against Grey Knights, I took more allies in the form of Dire Avengers and Fire Dragons (who took out a dreadknight!).

I'm not sure what to change or how to amend my tactics to be in with a chance of winning. Perhaps I'm concentrating too much on destroying enemy units rather than the objectives? I also wonder if I need more troops in order to claim those objectives?

Might have another game in a few weeks against Necrons who, so I've heard, are immensely hard in the new edition. Is it worth taking a redeemer against them? Or should I invest in some devastators? The Dark Reapers have been great so with the doom/guide combination but they're all wiped out by turn two because they're seen as such a threat. Keeps the guns away from my other units I suppose.

Any advice and guidance would be much appreciated and I'll post some picture up of the army ask stands in the next couple of days.