Wohoo I've gone to comiket last year. May I know first what do you wish to do by visiting comiket? Depending on your answer will of course give you different times to line up with the crowd. If you are like me want popular event-limited goods you may have to go early (die hard fans line up at 1AM at event day in the winter ) or if you just want to go and get a 'feel' on what is comiket you can come afternoon to look around the 3 different halls as the people will be 'lesser'.

FYI I went there quite 'late' in the morning on the first day, if I remember correctly I reached Kokusai Tenjijo Station (International Exhibition Centre Station) around 08:30AM and join the long line of people. I think I lined up more than 2km from the convention hall. (Refer to pics)

Took me almost 30 minutes of walking/lining up to reach the halls after the event started at 10am!

Then more lining up to the commercial exhibitors! Well at least I got some exclusive GSC goods by myself

Hmm, maybe I word it wrongly, walk to end of line 30 minute. Wait 1 hour to 10AM then walk 30 min to reach hall

Gotta walk (run) fast, the goods are being taken away in the hall

Now planning similar trip, with AA promo about MYR1.5k return with 40kg luggage

IINM, above 1,000,000 JPY (1000k) need to declare.

1. Go to train ticket machine/combini
2. Pay with 10,000 Yen
3. ???
4. Watch small change come out

My flight to Haneda with AA landed 30 minutes early. Cleared customs withing 30minutes and took the monorail to town centre. Managed to board the last train to my accommodation from Shinjuku. Didn't buy the Suica though. You can take the limousine bus if you worry on not making the last train.