Clueless Moments

I think of Alicia Silverstone circa 1995.

Then I see if any of my pieces can be improved, or if I can/need to give my king luft. Then I look for a safe waiting move if all active moves seem to weaken my position. But you really must form a plan of some sort.

(p. 83)
POSITIONAL PLAY

While you are still a beginner, you will find that opportunities
to make combinations usually occur haphazardly, through
simple oversights by you or your opponent. But as you
progress beyond this stage, these opportunities usually need
to be foreseen a move or so ahead, and in many positions
there will be no tactical resource available at all. Many
players find that the hardest part of chess to master is what to do
when there is no obvious plan of attack, or when the opening is
over and you are not sure what to do in the middle game.
When you do get to such a position, keep in mind these two rules :
1. Look around for any of your pieces which are not in
play and whose position can be improved ; if you can see
nothing more positive to do, simply move your worst-posted
piece to a better position.
2. As a general aim of your strategy in positions where
there is no combination possible and no likelihood of attacking
the king, aim at tying down the enemy pieces to the defence
of a fixed weakness in his position. A fixed weakness is a
pawn that cannot safely move and cannot be defended by
(p. 84)
another pawn, or a square in the centre or enemy camp
which it is impossible for the enemy to defend with a pawn.
Such squares are usually best occupied by your minor pieces.
In the case of a weak pawn, the fact that your pieces are
attacking it and your opponent's defending it will ensure that you
have the initiative and (usually) control of the greater part of the
board. Once you have the initiative, your chances of bringing
off a combination or an attack on the king steadily increase.

Barden, Leonard. 1959. An Introduction to Chess Moves and Tactics Simply Explained. New York, N.Y.: Dover Publications, Inc.

Attack the opponent's king.

More tips, this time my own:

(1) Advance your pawns to gain space, even if it's a pointless looking a4 or h4. This is what the computer does, and I've lost many games to the computer because those seemingly stupid pawn advances put its pawns close enough to the last rank that it could later make a sacrifice in the endgame to get one promoted.

(2) Attack something, anything, especially with pieces against pawns. That keeps the initiative, even if it's not a serious threat, especially since your opponent might just do something wrong when responding to that tiny threat.

(3) Alternate. Shift attacks from flank to flank, like a tennis player trying to tire his opponent.

(4) Similarly, probe weaknesses. For example, trying doubling your rooks, try invading with your queen, or anything where your opponent must respond. The longer the ongoing tests to which you subject your opponent, the more likely he will fail to respond correctly, then you've got him.

On the topic of patiently improving your position, here's a great video that somebody mentioned this week in the forums, regarding how to attack the Hippo formation:

()
Lecture with GM Josh Friedel (Games from the U.S. Championship) - 2014.05.21
https://www.youtube.com/watch?v=J-c-_QLCzc0

+1 on this thread so far.

You can also sometimes play in a restrictive manner by preempting your opponent's plan. In a manner of speaking, kicking the ball back to your opponent's court. This works especially well when neither side have distinct weaknesses to work with. If you can simultaneously improve your pieces position, then all the better.