problems in middle games

i play generally ruy Lopez openings as white in opening it is all fine for 10- 15 move but then in middle games i suffer a lot and not able to find good moves or u can say winning moves so how can i solve the problem

I think you'll have to learn some stuff called chess tactics and strategy.

thanks a lot any other way

I am soving tactics everyday but i how can i apply in real games

Magic pixie dust?

You need to learn to develop a middlegame plan.  A simple middlegame plan is the following:

1.      How to play the middle game?

a. In the middle game we need to start an attack.

b. We come up with a plan.

1)      We need to find a target to attack.

2)      We need to find a way to attack the target with our pieces.

3)      The easiest targets to attack are the opponent’s weaknesses.

i.        Weaknesses are the pawns or squares on the 5^th, and 6^th rank which cannot be protected by pawns.

The nature of tactics is that you're learning pattern recognition, so if you're really learning tactical patterns, they should just jump out at you during games. However, in real life, they don't always just appear as if by magic; You'll have to hunt for some tactics. The key is knowing when tactics are likely to exist and when they're not likely to exist, so you'll know when to spend time looking for tactics. Dan Heisman calls this the seeds of tactical destruction. Here's one of his Novice Nook articles on the subject:

https://web.archive.org/web/20131006111441/http://www.chesscafe.com/text/heisman05.pdf

As important as pattern recognition is (and it is very inportant!) what is equally if not more important, is knowing how to create a pattern you know.