I've noticed myself doing the same thing. Instead of looking for tactics, try and use your experience to tell whether a move is positionally good or not. This involves thinking about what your opponent's plans are as well as your own- it's no good to find a good sequence of moves if you haven't noticed that your opponent has a positional threat. It may not be that your opponent can win any material, but if they can reach a better position, then that can be just as bad.
Remember to make use of your experience. You're a 1648, so you're roughly the same as me- I think you will be able to tell whether a move instinctively looks strange or not. If it looks strange, it probably is! You should also remember that at our level people don't make so many blunders and tactical errors as they do lower down, so often the best course is to play positionally and not to take advantage of any unorthodox-looking tactics. Hope this helps!
I've noticed a trend in my recent games where I will get tied up in calculating tons of variations because I'm constantly searching for a concrete plan, and will forget completely about pure positional chess. As a result I may make horrendous positional moves rooted in poorly calculated variations that fall apart when my opponent makes an improvement on move 3 or 4 of a line.
Any tips on how to get used to thinking more abstractly rather than always getting tied down in a sea of (largely incorrect) variations? I like to play sharp openings, which may explain my insistence on tactical thinking -- my mentality is, I don't want to miss the opportunity for a knockout blow, and in order to spot one I'll need to be calculating. Obviously, this is true by nature of having selected a sharp opening repertoire. But for some reason I swing way too far in this direction and neglect positional concerns, and get myself into horrible positions which I usually go on to lose.