Kieren has pointed you to the place to look for information on how to do this. One thing I can add is that you might take the definitions of bookTitleMarkup and scoreTitleMarkup from
titling-init.ly as templates and work with them to get a custom look. I've adapted scoreTitleMarkup to get the increased space you want:
\version "2.14.2"
\paper {
ragged-right = ##f
scoreTitleMarkup = \markup {
\override #'(baseline-skip . 10) %% this will change distance between title/subtitle and composer/arranger
\column {
\override #'(baseline-skip . 3.5)
\column {
\huge \larger \bold
\fill-line {
\larger \fromproperty #'header:title
}
\fill-line {
\large \smaller \bold
\larger \fromproperty #'header:subtitle
}
\fill-line {
\smaller \bold
\fromproperty #'header:subsubtitle
}
}
\override #'(baseline-skip . 3.5)
\column {
\fill-line {
\fromproperty #'header:poet
{ \large \bold \fromproperty #'header:instrument }
\fromproperty #'header:composer
}
\fill-line {
\fromproperty #'header:meter
\fromproperty #'header:arranger
}
}
}
}
}
\score {
\new Staff { c''1 }
\header {
title = "Title"
subtitle = "Subtitle"
composer = "Composer"
arranger = "Arranger"
}
}