Obviously first of all we need a proper fishing water holding big pike. Then I recommend to study the water first. Find out about where are the deepest holes. Are there any old trees or similiar structure close to the bottom? If so, pikes like to stay inbetween the wildest underwater woods. The strongest pike usually takes over the best spot. If there is a deep hole, that is always a hot spot often holding a large pike.
We then have to check where most bait fish are usually. Sometimes pike have a spot in which they are lying most of the day and night before they swim of to enter their feeding spot. Depending on the water pikes can migrate quite a significant distance to the feeding spot.
Opposite to the old idea of pike always being on their own, they do hunt in schools in some waters. You have to find out how they hunt in your water. Then I check for a) the typical kind of baitfish available and b) what most other anglers fish. I try to imitate the baitfish unless too many anglers try to do the same. The bigger the pike, the more she has learnt. Finally pike very often feed nearly at the same time of the day again and again. This time window (often pretty short) changes throughout the season. Again there is no general rule. This is different from one water to the next one. It even may differ from spot to spot within just one water. Fishing a water offering crystal clear water the main feeding time may even take place within the dark night - especially during summer time.
Once you have worked out all the information you want to be in the spot exactly when the one big pike starts to get nervous or when she just has arrived in her feeding spot. Now you want her to see your fly just once but in the best (matching) movement. Slow or fast retrieve? That and the particular movement of your fly depends on the water temperature and what most anglers do.
What is good to keep in mind is, that big pike usually don't take a fly which has been presented to them several times during the none feeding time! So you may want to think about how to make it happen to have a meeting just once in the beginning of prime time. When that happens your line usually gets tight within just one cast.
If the water is crystal clear make sure to use the thinnest titanium leader. If the water is muddy this doesn't matter. If you are the only angler on your water this doesn't matter, too. Be careful about titanium it easily breaks within casting heavy flies. Extra smooth casting and an excellent timing is a must have here! Also the knots are important. I use the Albright knot (nylon/fluocarbon to steel/titanium) and the None slip mono loop (to connect the fly).
When I have a spot in which I know a serious big pike is around, I usually never fish long. Instead I prefer to fish just some casts and then start all over again the next day. Never I do the same cast twice. I change the position for every cast. Sometimes I may come back and fish a spot/stretch twice (in a row) though.
Above you may find some fine impressions about fly fishing for big pikes. During the last decade pike (fly) fishing has really become popular in my part of the world. I think that is for good reasons!
Oh, the best colour for a (big) pike fly? Colour doesn't matter as long as it is black! ;)
Here's one of my my favorite flies:
The Black Mamba
Catchy week to all of you!
All my best