It is very difficult to predict the right time to sell your tokens. I believe this the main problem so as most often the price is rising artificially.
Normally, if one invest in a project that one really believes in its future, we will hold on to it till we see a significant value which is absolutely impossible for a very good project to operate for good 2 years and not have a very big value higher than what we purchase.
When we also talk about the right time, we investors also need to give them breathing space, we contribute to why these projects fails, we do investment now and want to quickly reap within one, two or 6 months, at least we should learn to tag 2 years to every of our investments which we will definitely see very good value.