These instructions should give full details.
In summary, do this once to prepare your environment:
pbuilder-dist precise create
and for every release (from master):
rm -rf /tmp/build-collectd
mkdir /tmp/build-collectd
cd /tmp/build-collectd
wget https://github.com/rochaporto/collectd-ceph/archive/master.zip
unzip master.zip
tar zcvf collectd-ceph-0.2.0.tar.gz collectd-ceph-master/
bzr dh-make collectd-ceph 0.2.0 collectd-ceph-0.2.0.tar.gz
cd collectd-ceph
bzr builddeb -S
cd ../build-area
pbuilder-dist precise build collectd-ceph_0.2.0-1ubuntu1.dsc
dput ppa:rocha-porto/collectd ../collectd-ceph_0.2.0-1ubuntu1_source.changes
bzr branch lp:ubuntu/saucy/collectd
sudo apt-get build-dep collectd
cd collectd/
dch -i
bzr bd -- -S -us -uc
cd ../
debsign collectd_5.1.0-3.1ubuntu4_source.changes
dput -f ppa:rocha-porto/collectd5-precise collectd_5.1.0-3.1ubuntu4_source.changes
add-apt-repository ppa:user/ppa-name
apt-get source collectd=5.3.0
cd collectd-5.3.0/
dpkg-buildpackage -rfakeroot -d -us -uc -S
cd ..
debsign collectd_5.3.0_source.changes
dput -f ppa:rocha-porto/collectd5precise collectd_5.3.0_source.changes