well, especially when they are new is when they don't really stay in tune. I play a lot of stringed instruments, so what helps is the constant playing. You're breaking it in, so keep playing it. yes, you may need to tune it a lot, but I stretch the strings so that it stays in tune for that session. Take the string and pull it. That's how much it would have fallen out of tune.
again, it gets better over time so hang in there! (unless its older. if so...replace the strings.)
