It seems due to some logistic issues construction is very slow in tropico 4 (most of the time builders are idle with a long list of jobs). Is there any tips how to improve their productivity?
Make your workers spend less time walking.
Have skilled builders.
A skilled builder puts up structures much faster than a neophyte builder.
Rushing the actual construction.
Did I mention that building Garages will help?
(If you have the Modern Times DLC, a network of Metro Stations can help, but those get expensive pretty quickly; they're much better for tying together two different "towns" than getting your people from one block to the next.)
The obvious solution is to build more construction offices. Whilst this doesn't actually improve the efficiency of them (which I agree is pretty terrible, lazy lazy workers) it does in my experience get building work completed faster. It is especially effective if you build them at opposite ends of your settlement.
Finally, make sure that the work mode of the construction office is set to 'sweat shop' (default work mode) rather than 'take it easy' to make sure that they work a full day.
I've just noticed that a more thorough review was given in this question.
If most of your workers are idle with a long list of jobs, then there probably aren't enough trucks in your city to transport all of the goods and people. Build some garages to remedy the situaiton.
In addition, some other things that could speed up construction:
Most of the construction time is not in building time, but in transportation. Builders get there quick, but they may get back slowly. Or they might be sick and hungry or spend a lot of time away.
Build garages in faraway areas, especially for things like oil and mines which tend to be far away from the city. Construction will slow to a halt if they're walking back from all the way across the island!
Place construction offices near your city center. That is, make sure that there's enough housing for builders right behind the office. Try to place the church, clinic, market/farm nearby as well.
Quick build your construction offices and garages. Both are relatively cheap, and the production boost is almost worth it. There are plenty of faraway buildings which are not worth the transportation time as well, such as farms and fishing. Builders aren't cheap either; they're a lot of mouths to feed, so later in the game when you're making a lot of money, you should consider rushing cheap buildings instead of building a third construction office.