I've had a history of sinus infections in the past, but I've managed to massively reduce them recently. For previous ones, oregano oil sometimes worked well (not always, but often), and saline cleansing with the neti pot is also a great regular maintenance thing to ward them off before they start (I recommend also using the Varcho Veda "Neti Wash Plus" add-in for the neti-pot; a small bottle goes a long way).
However, the number one thing that made all the difference in the world in warding off sinus problems and ambient congestion in general, is changing how I slept. I'd traditionally been a stomach-to-side sleeper (start off on stomach, find myself gradually turning to the side in the middle of the night), and so I only used one pillow to sleep on, with my head being relatively flat (so it didn't hurt my neck when I'd try to sleep on my stomach).
But then after visiting an E.N.T. and looking at some CT scans and really understanding how the sinuses are structured, I realized that the way I was sleeping was preventing my sinuses from draining at night (my head was mostly flat, so a lot of gunk would just get stuck in there). So as an experiment, I decided to add another pillow (to raise my head more) and start off sleeping on my side from the getgo, so as to put less direct pressure on my face.
The results were noticable immediately. Very rarely was I waking up congested anymore, and the combination of that change and the neti pot have been keeping my sinuses feeling mostly clear for months now.
Anyway, think about how you sleep and see if this may be a factor for you too.
