Growth spirts occur based on your baby's actual due date, and regularly at the 4, 12, 16, 20, etc. week intervals (roughly once a month, although some are more productive than others it seems, but that's only from my own experience
).
And yeah, for some weird biological reason night sleep and day sleep are regulated differently in the body (I know it's in part due to the chemicals and their amounts your body releases at night vs. day, and your circadian rhythm). That's why a lot of babies (and adults, for that matter) seem to sleep better at night than during the day. However, one affects the other. The more rested your lo is at night, the better they take naps during the day, and vice versa. The more rested your lo is overall, the less chance there is of night wakings. Doesn't rule it out completely, but at least you reduce the chance.
Finally, sleep training, depending on when you start it and stick with it, and depending on your baby, can take from 3 days up to 1 or 2 weeks, roughly. It took mine about 2 weeks I think, but that's because I wasn't being completely consistant and there was a lot going on. She still doesn't sleep well outside her crib, which is a big issue. That's the next thing to tackle *sigh*.
You should start seeing results though within the first few nights as your lo learns the ropes. It may not be blatently obvious at first, but if you keep a sleep journal (which *really* helped me) you should see some results. The first few nights are always the hardest. And even after you feel you've succeeded, expect to have to take a few steps backward occasionally, as your lo changes patterns and cues on you.
*HUGS*
Sonya =P
