I didn’t take a photographs that frequently years ago, but I’ve often taken a photographs these days because I’ve hadbeen on a lot of business trips. I didn’t take photos that frequently years ago, but I often take photos these days because I’ve been on a lot of business trips.

1) People usually use the short version "photo", the long form "photograph" is only really used again and again in technical writing. 2) Present tense works here, because it's habitual

I didn’t take a photographs frequently years ago, but I’ve often taken a photographs these days because I’ve had a lot of business trips. I didn’t take photographs frequently years ago, but I’ve often taken photographs these days because I’ve had a lot of business trips.

Years ago, I didn’t take a lot of photograph frequently years ago, but I’ve ofs, but recently, I've startend taken aing a lot of photograph these days because I’ve had a lot of business trips. Years ago, I didn’t take a lot of photographs, but recently, I've started taking a lot of photographs because I’ve had a lot of business trips.

I think the only real correction is photographs instead of a photograph. I was just trying to find a better way to make it flow but your original sentence makes sense.

I’d also like to try taking fashionable pictures such as of my oil paintings for SNS. I’d also like to try taking fashionable pictures such as of my oil paintings for SNS.

"of" will come here, think: "(photos) of my oil paintings"

I’d also like to try taking fashionable pictures such aslike my oil paintings for SNS. I’d also like to try taking fashionable pictures like my oil paintings for SNS.

IThough I don’t completely don’t know how to do it. Though I don’t completely know how to do it.

If you meant to say that it very difficult and you don't any idea how, that would be: "Though, I don't know how to do it at all".

I completely don’t know how to do it at all. I don’t know how to do it at all.