Ok, some tips.
Fishing in the middle of the day is normally not much good. Evenings and mornings are normally best.
Look for changing weather patterns. After a long period of draught, sunny weather may stir things up. As may the opposite situation. I find thunderstorms to be good in general (take care if your rod is made of metal substances).
The fish species usually have a comfort temperature. Trout has 13 degrees celcius (arctic char 9). They usually choose a place that offers a good midway between optimal temperature and good feeding prospects. Good places are: Where the lake suddenly deepens, where rivers or creeks run in or out of the lake, inlets and on the tip of peninsulas.
In the spring and autumn. One can often find feeding fish in shallow bays.
I prefer spoon lures (traditional) and spinners (vibrax is my favourite). Don't bother with flashy colours, silver, gold and black is sufficient. Rapalas are ok if you have a boat. Bigger is usually not better with trout as it can be with other fish.
Torjus Gaaren