Texting Mishaps

Sending text messages is quite common here.  Everyone seems to do it, I think partially because it is cheaper than talking to someone.  However, this sometimes causes confusion because you don't have the tone of voice of the other person and there is a different grammar/spelling.  I now can read most of them pretty quickly but every now and then, I'll get a message that I have to read multiple times before I understand it (usually because it is a bunch of letters strung together that I have to "say" in my head before I understand it).  

In December, I went on a course up in Belfast.  While there, I met a few interesting people.  One of the girls and myself swapped numbers.  I texted her a happy new year message and from that we set up a time to meet up.  While texting back and forth to each other, she said "AM available" on such a day.  Thinking in terms of texting abreviations, I thought she meant that she was available in the morning and she was suggestingbreakfast.  So, I suggested a morning time and a couple breakfast places.  She texted back asking (thankfully) to meet up later.  Later, I reread her original message and realized that she meant "am" as in "I am available" so I sent her a message explaining my error and asking if she wanted later.  She agreed but had reread my messages and asked if I still wanted breakfast.  After many many messages (it really would have been easier to ring her but I wasn't sure of protocol for it), we agreed to meet at a reasonable time for lunch.  And we had good fun with a three hour lunch!  

Yesterday, I got a text from a friend that we were supposed to see in a couple weeks saying she'd need to reschedule.  Again, after a few messages back and forth, we found a weekend in March.  I sent her a message with LOL, we have to schedule in March.  Well, she didn't know what LOL meant and asked.  It took me two messages to explain it to her and that I was expressing humor that we couldn't find any common times 
in February.

These two miscommunications highlight some of the difficulties of texting for me.  I still don't know the etiquitte.  I don't know when to abbreviate or with whom (e.g. don't codeswitch well).  Usually I write the whole message and then start abbreviating when the othe person does.  I know there is a social code here, I just haven't totally figured out what it is.  Some of it is person specific of course, some may be generational.  Anyone out there want to tell  me the rules?