Learn as much as you can before fishing it!
In my case it is find the features, not forgetting the margins. Some margin spots may be obvious, slopes, rushes, snags, others not so like undercut banks.
I get the marker rod out, and map the lake as best as I can, and Google Earth can show up some real treats, as does an Internet search.
I had some lovely hand drawn maps of Virginia Lake at Earith, some Google maps of Nazeing, with gravel bars and distances to the bars, weed beds etc.
As has been said, other angler's can be useful. Don't 'pump' for information, but generally swapping info can get you a head start. Other angler's may have favourite swims and spots, might be all fishing the same, so doing what they do might catch you fish, but being different can catch you more.
Going back to Brackens pool, most angler's used very little bait, there was a rule of no baiting by hand, catapult or stick, so I went in heavy with massive PVA bags and stringers, often casting in as many as 30 bags or 30 bait stringers as I could in 30minutes or so, all ready tied.