The only way to make sure you catch the next bull run, is to buy as many coins as possible right now and to patiently wait. You can't time bull runs, but you can guarantee yourself an early seat by utilizing the market in its current form. The current stability that we can rely on between $6000-$7000 lends itself perfectly for accumulation purposes.
The block halving in 2020 is an extra factor of motivation to start accumulating right now. It might look far away, but the market starts climbing up far before the event actually takes place. OTC dealers and other parties will be out to fill up their reserves far before the block halving as well, and who knows, Bakkt might even be an extra trigger with their physically delivered Bitcoin futures.