Buying dips is one of the great advantages long-term retail investors (aka Financial Farmers) have over their sporting counterparts who are focused on short-term (read high tax) trading gains. Here's how to do it.
When you buy a dip your goal should be to add acreage to your financial farm...at a price YOU are willing to pay rather than chasing a stock up. Even before the market sells off 700 points like it did yesterday for example, an investor looking to capitalize should be ready. The first step prior to even making a shopping list of potential targets, though, is making sure you have investible cash not only ready to go, but preferably deposited with your brokerage. Sometimes in the heat of the moment cash can be transferred but remains "unavailable" because it hasn't been cleared. Always have cleared cash ready.
Now with your cleared cash ready, the other thing that should be handy is your shopping list. This is a living document which has been assembled after careful thought, research, and diligence. It is often updated with new information or thoughts. Regardless, this shopping list has as its basis a group of stocks you want to own and the price you're willing to pay for them. Price discipline is essential. During a dip you are a price maker instead of a price taker. That is an important distinction. Bid low.
Buying dips is a confluence of action and inaction; the financial farmer has cleared cash prepositioned and a shopping list ready, now comes the order flow. Selloffs are tricky in that they often come on the heels of unpredictable data, by that very metric investors don't necessarily know the full impact of that data on the moment of release. Sometimes there are global macro events that trigger massive flights to liquidity that unravel over days, weeks, and months. Sometimes it happens in hours. The future is nebulous. But the investor should be prepared for the worst. This means that a selloff can markedly accelerate quickly. Very quickly. That is why having a comfortable margin of error is vital on the purchase price. Use limit orders.
The other leg of the trade is the timing. Sometimes even if you get the stock you want at the price you want you still overpaid! Selloffs have a nasty habit of lasting longer and diving deeper than we think is possible, or even reasonable. That's why you should buy in tranches.
If your goal is to have a total 1000 shares of XYZ, consider buying the entire position in segments; make a an initial buy of perhaps 100 shares at the first price point (with a margin of err0r build in) that you think is reasonable. Then stagger those limit orders lower and lower and lower. The risk here of course is the opportunity cost of NOT getting your full desired position, but by using staggered limit orders you can ideally pick up some portion of your goal at pricing more favorable in to you. Stagger your order flow.
So to recap: Buying Dips is a great strategy for long-term investors who want to pick up stocks during a period of market weakness. The strategy involves having cleared cash ready to invest at your brokerage, having a shopping list on hand, and placing staggered limit orders. Although not foolproof, history has shown being prepared to buy quality stocks on a dip can result in meaningful gain over time. An old adage in the real estate world is, "You make your money when you buy, not when you sell."