I know some of methods for Sanger dna sequencing, maxam gilbert sequencing, pyrosequencing, automated dna sequencing which are used for dna sequencing. But I don’t know how for these method sequences dna?
All the methods u stated above involve complicated steps, not really suitable u ask people to explain all the detail from forum. I will recommend you to study each of them 1st, how they works to sequence the DNA, if you have any doubt on some of the steps, then u post your question here, I am sure many people will be willing to help you here… ^^
Actually if you go on Wikipedia, all those methods are extensively and correctly explained (except, as far as I know, the automated which is just an extension of the Sanger or pyrosequencing one, but automated to save human labour).
The different methods of next-gen sequencing
Illumina and SOLiD are about 35 to 50bp
454 pyrosequencing claims to attain 400 to 500 bp and that it will be able to reach 1000bp
Pacific bioscience claims that it will be able to go up to 1500bp with helicase based 3rd gen sequencing
Sanger based will give easily 700-800bp read in an experienced lab, 500bp if you are a DIY, and up to 1500bp if all parameters can be optimized (usually that is not automated).