Hi Vic, I can see why this is confusing to you, because all the three can be roughly translated into "to get". I'll first look at 取得 and 获得 as a group and then treat 收到 separately. 取得 and 获得 are very often interchangeable but they're still different in terms of shades of meaning. I think a better translation for 取得 could be "to secure", which means to get or obtain after a lot of effort. But 取得 has the sense of "being meant to be" or "assertiveness", it's as if the thing/goal you finally get is predetermined to be yours, except you still have to work hard for it. The result very often meets your expectation. 获得, however, has the sense of "being favored by God", so the object it takes is seen as a reward granted by God, because of your hard working or just because. The result is very often somewhat out of your expectation. You can use 得到 in place of 取得 or 获得; it's less formal and is neutral in meaning. As for 收到, it's pretty much like the word receive in English. You passively wait for something to get to you and then you accept it. The object 收到 takes tends to be a gift, a prize, mail, or a message-like thing. Ex: 收到礼物 (gift)/奖品 (prize)/邮件 (mail)/消息 (message)/通知 (notification)/命令 (order, as in instruction). Therefore, when you're given a book as a gift, you 得到/获得/收到一本书当作礼物, but I personally wouldn't say 取得一本书, because it sounds like I am a go-getter instead of a receiver. When you get a kiss from a girl, you probably would say 我得到/获得一个香吻 (literally, fragrant kiss, meaning a girl's kiss). 取得 or 收到 would be less appropriate because 取得 makes you sound too aggressive and 收到 makes you sound like a recipient of a letter.

PS The difference between 取得 and 获得 lies in the first characters. The 又 part in 取 is a hand; the 耳 part is an ear, so 取 is a picture of reaching out for an ear. In ancient times, our ancestors would sometimes cut off the left ear of a prisoner or captive and use it as a proof to get a merit from the government. Since a prisoner or captive is normally under control, the ear-getting thing is pretty much at your disposal. Hence, 取 has the sense of "meant to be" or "assertiveness". The traditional character of 获 is 獲. It's made up of 犭(dog), 雈 (long-eared owl), and 又 (hand). Therefore, it's a picture of hunting a long-eared owl or owls with the help of a dog/dogs. In ancient times, when you hunt a bird/birds, the result is pretty much at the mercy of God. Hence, it has the sense of "being favored by God".