If you don't mind it looking grey, teak requires very little maintanance, just don't let any blood/fuel/wine/etc get on it when it's dry, dry teak will stain, wet teak doesn't.
If you want it golden, that will require regular attention, especially if it's in the sun and/or get salt water on it.
If the teak is rough, first sand it with 120 grit to knock the grain down, then 220 to make it smooth. Always sand with the grain. IMO, freshly sanded teak is beautiful, but unfortunately, it doesn't stay that way long.
When it starts turning grey after a few months, you can use teak cleaner to make it golden again, I prefer Snappy Teak. It's a 2 part cleaner/brightener, but be careful, it is harsh on gelcoat and paint.
You can also use TSP (tri-sodium-phosphate) which you can get at a hardware store or Cascade liquid dishwashing detergent. With both of these,
DO NOT apply them directly on the teak, mix them with water in a bucket first. These will bring back some of the golden color, but not as good as the marine products.
I'm not a fan of oiling or staining teak. Eventually, mildew and dirt will find it's way under these products, and then it's that much hard to get back looking good.
Finally, I hope my yacht experience can be helpful on this site
Lloyd