How to break 1700 uscf? Also, if you could answer another question of mine, how to break the 2300 rapid barrier?
The same way you improve at any rating level: evaluate your weaknesses, and try to work on it. If you're bad at tactics, solve puzzles each day. If you lack in positional understanding, read a book, do some research, etc. Different things work for different people, and we all get stuck at different rating levels. There is no magical formula to cross any specific rating point.
last advice for me,
what tips for the symmetrical positions ?
example of symmetrical position : 1) c3-c6 2) d4-d5
Develop your pieces - don't try weird stuff just for the sake of "mixing up the position"
On the other hand, if you can, try to create weaknesses in the position. Don't just copy your opponent's moves. Then, you'll obviously get a dull, equal position