A few tips:

1. You have the best chance of succeeding when you diversify.
2. Find a coin that has a specific utility (i.e. there must be some functionality behind it). If the Bitcoin bubble does perhaps pop in 2018, these coins with real functionality will be the last ones standing.

I recommend the following for 2018:

- BTC (not more than 40% your portfolio)
- ETH (invest as much as you can)
- ETN (invest as much as you can)
- LTC (the race is on between Litecoin and Bitcoin Cash to see which one will be the true transactional coin)
- BCC
- IOTA