Marathon training and race

If you come from 10 kilometer races, long runs are slow and personally I don't like to run at this speed level.

It is like driving a car. At the beginning the fuel tank is full and we can go any pace - theoretically. But the faster we go the faster we need to refuel the tank. Our range depends from pace. Training long runs that are faster than competition speed can increase the fuel tank.
This is how it worked for me.

1. If you try to be good at all distances, than it is hard to increase speed in all disciplines. I do not try that. I concentrate on one distance and after the competition on another may be with a totally different training plan.
2. Of course I did not run a marathon in race pace in training. But why not 30 km? I even tried 37 km once in 9 weeks marathon preparation.
3. Marathon is a Brain-Run. If you know, how long you stand a high pace on long distance, it is easier to convince your body.
4. Ask you this questions: What about your current training? Why do you want to change something? If you think there is no real improvement, try something new like additional sports, or less frequent training but therefore at higher pace. 
5. For the marathon competition I run 1:00-1:15 minutes slower per kilometer than in 10km competition. 
6. Marathon training shall include the right nutrition. That must be tested in training before. 
7. Don't orientate at the pace of other runners. Most oft them are slower or even faster than you (for the moment). Keep your own pace. The marathon challenge is to keep a pace for at least 3 hours (plus a bit more) and to plan the pace in advance - not to fast and not to slow. Therefore I listen to my body to figure out, what are the reserves. 
8. Run at constant pace right from the beginning. That is not easy in a crowd of people. 
9. 2 weeks tapering before a marathon 
10. Be careful! Don't risk too much! There are a lot of possibilities for an accident during the competition, because of the amount of inexperienced runners and inattentive audience. There might be also a tripping hazard on the track. From 30-42 km your legs are not fresh. A sudden move can bring you in trouble. 
11. Take your time to recover after a marathon! Don't start to early with hard training for the next challenge. 
12. Listen, read, rethink other experiences!