If you're between, let's say 2k to 25K, slowly buy in an accumulation phase of an altoin. But of course you don't pick the first one, research are a must.
If you want to invest in very long, BTC is still a good boat, but buy and wait that's it.
BTC investment is always good option. Please make some sense that the market of btc is expanding. But we know that it is not sure when the price will go down/raise, generally 2 approach you have to follow to gain profit or stay in the safe path: 1.Purchase the btc when the price is less and 2. sale it when the price is high. But anyway you must have the patience to wait so that you wont regret by taking the quick step for investing or selling. the btc world is growing well so very unlikely that it will become obsolete.
Patience is not the problem here, it's timing. Everyone can be patient, everyone can wait for months before making a move on his bitcoin investments. The problem here is identifying when is the price actually a low price and when is it a high price. You can't simply base these things on the previous price because it can still move further.
For example, it's $1200 today and the price goes to $1300 the next day. You sell your coins at that time because it's "high" and then the next day, the price went to $1400. There's no way that you can know if the price is already a good time to buy/sell unless you're an experienced trader and you know all of the latest updates.