Every time you get acquire a living animal. It is important that you learn as much as about it as you possible can. This naturally goes for spiders also. So you can make sure that the animal has the best living condition as possible.
With bird spiders it is especially important to know what spices you have and were it comes from. Because there are over 800 spices spider. Some live in a rainforest and some in a dessert, some in tunnels in the ground the last kind live in tress.
Of cause you don't take care of the different spiders the same way. Some need to low and some need higher/higher air moisture. There are mainly 3 different kinds of spiders tarantula (bird spiders) :
Surfers living spiders: This that mostly are on top of the ground, and this are were we are able to find some easy specimens. Most often it is all about having a gentle (non aggressive) and beautiful to make it popular. Grammostola spatulata, Brachypelma smithi and Lasidora parahybana are the Latin names of some that are good for a beginner.
Tree living spiders: As the name say's you can guess its spiders that live in the trees =). These types of spiders are often very fast and can be a bit aggressive. For beginners I would recommend Avicularia avicularia or Psalmopoeus cambridgei. For the more trained you could use Poechilotheria's.
Tunnel spiders: Live most the live in Tunnels they dick underground this group can be hard to handle and I would not recommend starting with a spider like this. From this group you can find Haplopelma, Citharischius and Ephebopus.
And just to make sure bird spiders are not "pets" they interest animal's, kind of like fish. Because it is not something you take out and touch like a mouse. They are best to remain in the "natural" environment. It is normal that a spider can die from stress because of this. On top of this, spider can't take getting dropped/cut. If a spider gets a cut they will bleed to death. Because the blood can't plug the hole like we can.
Spiders however don't require wry big terrarium, IF you give them everything they need, main issue is food and water, but you also need to build the terrarium different depending on what kind of spider you have.
The biggest part of the spiders come from tropical country and that is why it has to be "warm" about 23-28� C in the day and about 20� C at night. Rainforest spiders often need about 26� C in the day but here the temperature don't go down much. You should have something in your terrarium to measure the temperature.
Some spiders need to have low humidity some need to be high. It all depends on were they normally live, desert spider of cause need low humidity and juggle spider need high humidity. You should have something in your terrarium to measure the humidity. Low would be around 10-20 (again depending on what kind of spider), and high is 60-70 (also depending on what king of spider. Some spiders may like even higher humidity.
But maybe most important you need to keep your separately or they will ear/attack each other, they should only be brought together for mating. But also here you risk that the female kill the male spider ( this is the way it works in nature ).
Food: Spiders will eat almost every kind of inset's but, it's different from spider type to spider type what the most common food is.
Tree living: Mostly eat Moth.
Ground living: Mostly eat beetle's, grasshopper and similar bug's.
Tunnel living: (same as ground living) Sometimes spiders eat animal's like frogs and bird offspring. It is a good thing not always to give your spider the same things. So it don't eat the same all the time.
Grown spiders should only get food 1-2 times per week depending on the size of the spider, and the size of the prey. It is best to feel the smaller spiders, more often and with smaller pray compared to the size of the spider. Spiders can eat big things but you should be careful.
When the spider change the skin/molding
(it need to do this to grow) you should not disserve it. Because cause it need's to lie on the back.