Part of me thinks I should just invest in a number of coins I think have a long term future and forget about them.

Yeah, I'm not so great at trading / investing either, and I've come to the same conclusion - invest based on fundamentals for the long term and don't get caught up in the volatility roller coaster.

When you do see huge increase, like we saw with Dash, it just might be prudent to take some profit while holding a percentage. Decide how much of a minimum position you want to maintain and sell the rest for a tidy profit.

Another thing to consider is that even a small position could yield huge gains in the long run, so weigh that in your minimum hold amount.

You could also divide your crypto portfolio into ranges, where each range represents a different criteria for when to take profit and how much gain items in that category must make before you consider selling any of your position in it. If you think about your goals ahead of time and not in the midst of a volatile swing I think your decisions will be more rational than emotional.

Anyways, those are just a few items off the top of my head, not that I'm advising you. I know you're wiser that to take anything I say about investing as wisdom :)