Tweaking Kodi
Once you Kodi setup is working there are number of improvement you can make.
For folk using Raspberry Pi there are a number of options. One that may be usefull is that the Raspberry Pi looks for an HDMI output when it is powered on. Sometimes it may start up fast than other equipment.
If the Raspberry Pi does not sense an active HDMI output on boot it will default to not sending any HDMI output and sending the video to the composite output. So no picture appears!
To fix this the CONFIG.TXT can be updated.
If you don't want to use command lines tools there is an easy to use GUI add-in
Command Line
http://wiki.openelec.tv/index.php/Config.txt
Gui Add on
http://www.htpcbeginner.com/edit-openelec-config-txt-openelec-rpi-config-addon/
Note these tweaks also allow overclocking and other parameters to be set. I'd recommend only making one change at a time and performing a reboot after each one to check things are working. If you to brick your setup make sure you have all the things needs to reflash your memory card
Image of the current SD card or the stock OpenElec build and a copy of you backup file. REMEMBER to keep this somewhere other than the SD card! Also files on the SD card like backups are NOT VISIBLE if the card is read in a card reader. I find it easier to copy files off to a shared network location. while the RP is running.
With older hardware like the RP Model B overclock might help. On the Pi2 you can over clock if you need to but I've not seen a need for this.