Looking for advice for investing large sum I would like to make a relatively large investment into ETH and I'm looking for advice with my strategy. Obviously I would hate to make this investment at once now and then ETH immediately drops down to $120. At the same time if I wait and ETH jumps to $250 I would be equally pissed.

Is there a certain strategy to making large investments to help mitigate potential losses in these cases. For example, invest x% then wait until y happens then invest z% more?