help :(

I watched sc2 for about a year, so I'm reasonably familiar with the game and absolutely love it.  I recently got my hands on a copy and was pretty excited about playing it.  trying protoss, stuck in bronze.  keep telling myself 'probes and pylons', but still get supply blocked and/or miss probes semi-regularly.  however, even when I feel like my macro is better than my opponents (e.g., more mining bases with still low resources, more production facilities etc.), my armies simply get crushed.  for example, against a terran bio-ball I tried both colossi and ht, but neither worked particularly well - my (200/200) armies just melted away time and time again.

I really don't want to give up, but it kinda sucks atm.  do any of you have any tips on how to (for a noob) improve general mechanics - macro, micro, learning counters to unit compositions, multitasking etc.

p.s. rushes/all-ins get me every time.  but I don't want to respond in kind (i.e. 4-gate) because that doesn't really teach me much.