When more recent sales are at a lower price than older sales for similar properties, the market is declining. Ditto listings.
There may be other indicators that the market is getting ready to decline like longer days on market. You can't get out of doing the tedious work to analyse the market trends. If you've never done it, it becomes much more important when the market is changing and you'll need to step up.
Jim, I was going to email you a pdf document from one of my clients which explains exactly how they want me to prove market conditions in my reports but your PM is turned off. Depending on your data sources, this can take several hours but once you have done the initial work it is easy to update.
Seriously, I use days on market, pricing history, and current listings of similar homes in the same neighborhood. If you have not been following similar threads on the forum, you should note that market trends can change from neighborhood to neighborhood. Most communities have sub-markets. In my area, most very high end neighborhoods have not been seriously affected.
Some lenders have created lists of counties and/or cities where they will NOT accept a report that shows the market as stable without substantial documentation to prove it.