Before discussing anything about the Indians, I'd like to say that the tribes of the same level of development do not differ in attitude. All "Tupi are friendly", "avoid Arawaks" etc. are baseless.
Indians' attitude depends on game level and your behavior - how far from them are you keeping your colonist and military, how often do you trade with them, attack them, or steal their land (before Minuit), how many missions have you established, o you have Pocahontas, are you playing French ? These are the basis of your relationships with Indians, not name of their tribe.
As tribes of different level have varying characteristics, it's fair to assume it has some effect on their attitude, but mainly by secondary factors - you're more likely to have big trade with more civilized Indians, take lands from agrarian tribes etc. The difference is however rather minor.
Prepare for a big war against Indians. If they're close to your colonies, they will attack, either because they just don't like you, or because the king pays them to. (Unless you play French, get Pocahontas early, establish many missions, trade with Indians a lot and have some luck, in which case you *may* avoid it, but you probably won't *want* to avoid it)
Many benefits come from attacking Indians.
First, you get the treasures. They're really worthwhile in case of the high-tech Indians (Aztec, Inca), but a bit of free money from the low-techs won't hurt either. Cortes greatly increases amount of treasure you can get, so get before you start a campaign (unless you have to do it earlier to protect your colonies).
Second, if you have a mission in the village you're attacking, there's a big chance that they will join you as converts. Converts are quite useless in mid and late game, as you should have a lot of outdoor specialists, but you can convert them all to free colonists with Casas. Chances for conversion are pretty small without Sepulveda (I think it's more likely to loss a missionary than get a convert), so get him or don't establish missions during attack. I don't know how missionary's expert status (Jesuit or Brebeuf) affects that chance.
Third, attacking Indians is the easiest way of training your soldiers before the war against king. After you have George Washington, every successful attack results in soldier getting promoted to veteran status. And occasional failed attacks result only in loss of 50 horses (50 horses for upgrading 3 Free Colonists to Veteran Soldiers is a good exchange).
Fourth, free land.
So just before the Independence War kill all Indians you can find - you will get money, colonists, train your soldiers, and get rid of Indian problems.
A very important thing is that after you destroy Indian capital, they become calm again. So if you plan a war to get more territory, destroy all small villages you want first, and only then their capital.
Trade with Indians
If the Indians live near some other power, are at war with them, and live far away from you, selling horses and guns to those Indians may be a feasible option.
But always think twice about that - it's like giving weapons to Afghani mujahedeen, for them to fight the Soviets. Even if they actually harm the Soviets, won't they use it against you later ? What if you decide to assimilate those former Soviet lands ? ;-)
After some experimenting I found that Indians usually get enough guns and horses without your help, and ratio of harming your opponents to guns/horses sold is relatively small. Still, they'll pay you a lot (prices in 500-1000 range are usual, unless they already have too much), and you may consider harming other Europeans an extra premium.
When you're sending a scout to a village (that's a good idea, because of the monetary gifts you can get), remember to write down what do they want, what are they selling, and what skill you can learn there. If you won't note it and need that information later, you're going to waste precious scouttime.
Sell them trade goods, maybe tools, buy silver, cloth and coats. And sell them the stuff they want/need, if you happen to have it and they pay better than Europe. Trade with wagon trains, Indians don't like trading with ships. Price negotiations can be risky but very profitable (some people will surely do save/try/load/try again). I don't like the way negotiations work in the game for that reason. If you want to buy and not only sell, send them a Wagon Train, and they will sell you as many tons as you sold them. If you use a ship, you will be offered only 1/4 as much as you sold them.
I think the Indians won't buy the same thing twice, so you may think about alternating between 100 units of something profitable (tools and trade goods) and 1 unit of something you're selling at loss (cloth, coats, rum).
The whole Indian business is just some extra money - maybe even quite a bit of extra money, but it's not going to be your main source of revenue.
Treasures
The easiest way of transporting treasures is to get them to the coast, set a temporary colony with a scout or a soldier, have the king transport the treasure for you, and disband the colony. After Cortes it's for free. Before just pay the Galleon fees, as you don't have any other option.
Going with the treasure all the way to your colonies is a huge waste of time, and there's a very big chance of it getting attacked by the Indians, even if escorted.
If you have a Galleon, king won't offer you a transport, so send it to get the treasure (no need for a temporary colony).