When it comes to what exchanges, I want you to play safe and just prefer big exchanges and the most trusted one. Now, when it comes to altcoins, I prefer you do invest on cheap coins and do a long-term hold in it. There are still cheap coins out there that are lower than $1 and still good like in the top 50 coins.
why do you think of cheap coins? coins have low prices because they have a very large supply. that's not a good analysis. if you want to invest long-term you can buy assets that have attractive plans in the future. EOS might be an interesting coin for several years to come. but if you want to invest in short-term or daily trading, you can choose assets with busy trading. it will foster a very fast market movement.