The Kittens' First Three Months

The first three weeks

the mother cat will spend most of her time in the birthing box, and the first 24 hours she will on the whole only leave it to eat or go to the litter box. Later she may take longer "recesses", but will run back to the box at the slightest sound from the little ones.
Most mother cats are extremely proud of their litter and accept all admiring statements with delight.
The kittens don't do much more during this period than to suck and sleep (and grow). It is, however, normal that they don't do so much about the sucking during the first 24 hours, and therefore stagnate in growth or even lose a little weight.
You should weigh the kittens every day during this period. The most common rule of thumb says that the kittens should gain their birth weight each week. A kitten which at birth weighed for example 85 g, should therefore gain about 10-12 g. a day.
The weight gain - or lack of said - is a very reliable indication of whether the kittens are doing well. If it is a

very large litter, some of the kittens may have trouble getting a teat to hang on to and may need supporting feeding with cat milk substitute. In other cases missing or poor weight gain in one kitten may indicate you should see a vet about it.
The umbilical cord will dry up and disappear within the first few days.
The kittens will open their eyes after about a week, and during this period you should see to it that their box is not exposed to too sharp light, which may be heavy stuff for eyes that are just beginning to function.
Otherwise one should not spare the kittens too much as to common sense impressions - since they will eventually have to leave home for a life as family cats and therefore it will only do them good to get used to the various sense impressions that go with family life.
Do not panic if not all kittens open their eyes at the same time. It is normal to see a difference of a day or two as to when the kittens open their eyes, and it is also normal that a kitten does not open both its eyes at the same time.
If the eyes have not opened after about 10 days, you may try bathing the crack between the eyelids with a little camomile tea. If this doesn't help, or if you observe yellow matter in the crack, you should consult your vet.

Another female entertains the kittens while Mom is out

Imprinting

Most mammals have a so called "imprinting period". It is a period in the animal's life, where it is especially sensitive to learning, so that what it learns during this period, will be especially well integrated in its mentality.
Often the main thing to be learned in this period is to know which species you belong to. Cats also have a period like that, covering the second through the seventh week of their lives. Popularly speaking it is during this period the cat will learn that it is a cat, and also here it should get the impression that humans are some sort of "species fellows". This is actually necessary for the cat to become properly tame and be able to function as a family pet.
It is therefore important to give the kittens as many positive

experiences with humans as possible during this period, and at best with as many different humans as possible.
All breeders have their own rules of thumb as to how this is handled best. Some say that each kitten should be in hands at least an hour every day, others have other rules etc.
One may also choose to "follow one's heart". Personally I cannot help but "fiddle" with the little ones all the time, and it is not possible to "pet them to death" or "wear them out".
During the first weeks, where it is important to weigh them daily, they will automatically be in hands at these occasions.

Things will really start humming...

from the age of three to four weeks. By now the little ones will be so lively they will start checking if it is possible to get out of the box, and now the "verbal" communication with their mother starts for real.
At this point it will be a good idea to move their box into a playpen (where you have closed between the bars with cardboard or the like), or into a small room that can be closed off so that only the mother cat can get in and out, or some other limited area. Then the little ones get

the opportunity to venture out into a small portion of the outside world and gradually try their strength against it.
It will be a great idea already at this point to place a small litter box with low, "kitten friendly" edges there as well. The mother will often start using it, and thereby demonstrate to the kittens what it's for, even though they haven't started eating by themselves yet. Since it is quite normal that the kittens at first check out if the litter is something you can eat, you should not use the kind of litter usually called "compact litter" - it may behave quite disastrous in a kitten stomach.
Place some kitten food there too already now. The mother cat will start eating it, and when the time is up for the little ones, you may be so lucky that their weaning goes off automatically this way.

The Weaning (4-5 weeks)

is normally not as difficult as you may hear. Some kittens start eating dry food by themselves quite without transition. Others need to have it steeped in the beginning. "Difficult cases" use to learn it by means of for example jellied sardines or other things with a strong smell, especially if you smear their noses with a bit of it; they will then by reflex lick it up and then find out it's not so bad after all.
Do not be shocked if you haven't seen small kittens eat before: they are not so good at etiquette and don't know it is not good behavior to stand in your food while eating etc. It may be a disgusting sight the first time you see it!

Often the kittens will still get a drop from Mom after they've started eating by themselves - just for the coziness of it.

All Over the House

I shouldn't like to give an exact time for when the kittens are old enough to be given access to all your home. It depends on whether their motor function and intelligence are well enough developed, and this is very different from litter to litter.
My own rule of thumb is that if they can manage to climb out of the playpen I normally use by themselves, they also have the motor function and resourcefulness to manage in the rest of the home.

Vaccination

Kittens should have their first vaccination at the age of twelve weeks and a follow-up about four weeks later. After this, they should be vaccinated once a year.

Vermifuges

- should be given a couple of weeks before their first vaccination (at twelve weeks).

Kittens will often fall asleep in the most peculiar positions from one second to another.