Dofile("filename.lua") -- load this file before parsing and executing

--This block contains helper functions
function create_advice_transportation_with_base(guid_string, base_advice)
   local a =  advices : create_advice(tonumber(guid_string, 16), base_advice)
   a.type   = advice_types . TRANSPORTATION
   return a
end
-- Helper functions do things based on LUA system script and constands from advices such as a.type

a = create_advice_transportation('2a355b3b') -- Advice ID to create
a.trigger  = "game.g_month > 3" -- Triggers for this advice. IE game months over 3
a.once = 1 -- Execute this advice only once per game
a.timeout = tuning_constants.ADVICE_TIMEOUT_MEDIUM -- How long the advice takes to timeout
a.title   = [[text@ea50e830  Celebrate City Birth--Roads Make Perfect Gift
]] -- Text reference for locale.dat. Otherwise show this title.
a.message   = [[text @aa50e837  Greetings, Mayor. I'm Glint Wheels, your transit man, here to give you the skinny on moving in the city. You can really put a shine on #city# by placing some roads in good spots. And think of the city's zones--the exchange of goods and services can't go anywhere unless they're connected by roads. You could even zip a road 'round each zone--touring your great city will be easier than ever, and your Sims will be singing with the tops down.
]] -- Text reference to locale.dat. Otherwise show this message
a.priority  =tuning_constants.ADVICE_PRIORITY_MEDIUM -- Advice priority on the list
a.mood = advice_moods.GREAT_JOB -- Advisor s3d model mood
a.type = advice_types.TRANSPORTATION -- Advice type.
a.frequency = tuning_constants.ADVICE_FREQUENCY_MEDIUM -- frequency to show advice
a.news_only = 1 -- show in news ticker only. not with advisors
a.event = game_events.NEW_CITY -- Execute on this event

-- This will try to execute triggers for all registerd advices 
-- to make sure they don't have any syntactic errors.

if (_sys.config_run == 0) -- if the config option is set to 0 in the _sys.lua, then
then
   advices : run_triggers() -- Activate all triggers
end

Here's the section declaration table for all advice

base_advice = 
{
   _base=nil, -- no base advice for itself
   guid = 0, -- this will be persisted in saved games and will have to be set to each advice by hand. 
   class_id = hex2dec("8a09f5f4"), -- C++ advice class ID (cSC4Advice class by default) 
   type = advice_types . NULL, -- NULL types never get triggered 
   mood = advice_moods . NEUTRAL,
   priority = 100, --0 to 100 scale, 100 = highest
   title     = "",
   message = "",
   frequency   = 720, -- in days, 30 days min
   timeout   = 36000, -- in days, dissappear msg
   trigger   = "0", -- never trigger this one
   once   = 0, -- show this advice only once
   news_only = 0, -- set to 1 for news-flipper messages only 
   event = 0, -- this has to be a valid event ID (see const file for the event table.)
   command = 0, -- game command to trigger along with the advice message
   persist = 0, -- if 1, message will remain visible once triggered whether or not trigger condition remains true (useful for random triggers)
   effects = {} -- Here is the format : a.effects = {effects.POOR_FIRE_COVERAGE, effects.UNHAPPY_SIMS}
}

These are the things that can be called during an advice. You've seen an actual advice sample above so this should be easy enough to understand :)