Help Keep A Yucca Alive!

[maggiemcgill]

I have had a plant (I'm pretty sure that it is a yucca) for about 5 years, I've managed to keep him going, but just as he starts to perk up a bit the tips on the leaves start to go brown.

Has it has grown I've re-potted & regularly spray the leaves with water; I also add baby bio as per instructions when I water it, but still the tips go brown.

Also it leans to one side which I rotate regularly as it starts leaning one way towards the window/sun.

Can anyone offer advice has how to care for this plant properly.