first know the basic - key sign, time signature, the notation itself

get familiar with the rhythmic part first ( tail ) - triplet, quintriplet, off beat. (if u check out guitar mag, they use tab with the tail to help reader with the rhythm.

the note of course represent by the dot. not the hardest part for me. only need to be memorized.

i'm still prefer tab for my notation, don't know when would I concentrate on reading notation.
but yes, sight reading is an advantage for guitarist. but u need to work on it.

it's better if u state what u want to know then

ok for me some part of it is essential for all guitarist to at least know about them.

for example, the rhythmic pattern. even if u read some tabs out there, they still come in rhythmic notation (tail).

why is this important? to help you precisely play your your notes on time of course.

help you practise with metronome and other thing. it all came from the notation.

and is it important to master sight reading?
if you ask me, my answer is yes and no.

if youre on a band which everyone rely on notation to put things together (should be really serious band lah this, or maybe sessionists band) then it's important to sight read.

but if you are on a band that simply play cover which u can rely on tab (which 90% u already know the arrangement, your line) then it can be pretty optional to have the ability of sight reading isnt it.

so i guess, the first is to know in what scenario are you now.

after all that's what i think lah. maybe it doesnt goes everyone's way.

lol, i tot what was the problem.

like xMika said lah, hear the song.
big part of music is hearing, not reading