To launch applications on login, just copy the relevant .desktop file from /usr/share/applications to ~/.config/autostart (you may have to create this folder first). This will autostart applications for your current user only.
Make sure you "Show hidden files" in order to find the .config folder in PCManFM; it's in the View menu.
All the universally autostarted applications are in /etc/xdg/autostart. In order to prevent some of the unnecessary services from starting at login, just delete or rename the files there from xxx.desktop to xxx.desktopbkp. To return them to their previous auto-started status, just rename them back again.