There is no definite answer to your question as everyone has different ideas on what makes a good investment. All i can say is to do research and invest in coins in which you see potential, remember just because a coin is feature rich does not mean that it will succeed NXT being a prime example. Personally i am invested heavily in bitcoin, litecoin, peercoin and dogecoin as these tend to follow each other when BTC price increases. They are also some of the oldest altcoins around and have considerable staying power. They are also all in the top ten at coinmarketcap.
Apart from those i am also invested in primecoin, foldingcoin and namecoin. Namecoin and primecoin have great potential if they can be developed further. Foldingcoin uses pow mining to find cures for diseases so my investment in that is more of a donation to miners. I was also invested in dash at one time but after a lot of scam accusations against the devs and my own research i decided to sell as it might be a scam, it's price over the last 3 months has also tanked 40% and that further contributed to my decision to dump dash.
All in all do your research, buy coins, put them away and hope the price goes up. It's all or nothing in the crypto game.
All or nothing. Yes eventually, long run.
Every big winner has to go through a transition stage of dramatic price increase, so a small amount in each of a few speculations is good.
A good portfolio should include alts of very different sizes and types . A core of large ones : (ETH, Dash, Doge) The older small ones undergoing revival or technical improvement are a fair bet. (eg Supercoin, Hobonickels, Cryptobullion). Plus a few with very different hash/profile (Primecoin, Monero VPN).
With the smaller coins, it's important to check that the wallet works well, the dev is active, there is a good block explorer, and an active forum.
. What other weed themed coins can say that? 
