What to do when the basic principles aren't enough anymore?

I consider myself to be just al little bit ahead of the beginner status. (current Elo OTB : 1475).

As a beginner you don't study opening, I know, you just follow the basic principles. But what's the next step?

Surely it's not knowing al the variations by heart. But only following the basic principles is not enough any more. My opponents (otb) usually have 30+ years experience and they outplay me in the opening en build up on the smallest advantages until the endgame.

So now what? Somewhere on these forums i've read the advice 'pickup a few opening and study the general ideas behind them'. Seems like a good advice.

But how do you do that? How can i pickup  few openings, when my opponent still has the right to respond any way he likes? ;-)   Should you look for some kind of 'narrow' opening repertoire? Or are there some 'families' of openings, which all have the same basic ideas? 

For instance: As white: I play e4 and try to studie a bit of the spanish and italian lines. Against sicilian I just respond with c3 (anti-sicilian) as to avoid all the 'theory-heavy' sicilian lines. But still, the main ideas behind the marshall attack or the berlin (which is basically for black to decide ) are quite different.

This is just an example.  The quenstion is: what to do now?

Just find some openings you like and pick a line you like. Learn some opening moves and what to do against common responses ( you can look in a book, database or on explorer ), some common ideas behind it etc. Nothing too deep just enough so that when you reach the middle game you know what to do next and to avoid common mistakes and traps. Play some games to get a feel for the positions.

Keep it narrow at first. One against e4/d4, something against c4 that is similiar to your response to d4 and something straightforward with white. Avoid overly complex openings where you have to know lines to not get killed, like the Grünfeld or Sicilian Najdorf.

Until you're very strong (probably titled) you'll want a set repertoire of single responses to all the major moves you face. Playing multiple responses to say 1.e4 just multiplies your workload and  it's hard enough maintaining a single opening tree. As for where to start to learn something new, Chess has lots of free resources, YouTube videos, games databases, short and sweet chessable courses. If it's prepared by a titled player it usually won't lead you too far astray. I've sifted through quite a lot of openings trying to find a repertoire that suits me and will share my strategy.

General principle is replace what isn't working and keep what does work. When learning something brand new I look for quality videos that focus on ideas. Lately I've been finding them in chessable short and sweet courses, but mileage may vary depending on author. Another good launching point is to see if Daniel Naroditsky has a speed run video in it. That can be hit or miss as sometimes his opponents play something strange and collapse, but he is one of the best at explaining his moves. Then, once you have a handle on the general ideas of an opening start playing it.

Refining an opening repertoire is simple but hard. When you lose to a move look up what to do against it and commit that plan to memory. If you find a whole variation isn't working for you replace it. Here I like to use master game databases although if you can find a course that aligns with your repertoire that works too. 

Anyways that's one strategy if like me you prefer to choose your own adventure in chess. The other alternative is to learn some one else's repertoire. Two ways of doing this is picking a favorite high level player and copying their moves or buying a prepared course  and working through it. I like this less as your playing "someone else's moves" and while you're certain to get decent positions they may not be to your tastes.

I understand that, thanks.

ie.

I once read that the scandivian is a very forcing line for black. That is: there aren't too many sound responses for white. You allready know white will capture and that white will develop the knight with tempo. So that makes preparing a bit easier, I guess. Allthough i don't really like that opening, it probably reduces your workload as black. (not too many branches to study)

Do you know of more such openings, in which the tree doesn't 'branch' too much, or if the tree DOES branch out a lot, where the main ideas stay the same, most of the time?  And would that mean such an opening is good for beginners facing experienced players?

Again an example: When i should choose the italian as white, then it's basically up to black to decide how sharp the game gets. The main ideas behind the two knights defence or the giuoco pianisimo couldn't be further apart from each other. And it's black who choses between the two. 

I guess this is a really common 'problem', which is the very nature of chess. I just need some help from experienced players facing it.

#1

"what's the next step?" ++ Tactics and then endgames.

"only following the basic principles is not enough" ++ It is up to IM level

"they outplay me in the opening" ++ If you play solid moves, then they cannot outplay you

"'pickup a few opening and study the general ideas behind them'."
++ Pick 1 defence for black against 1 e4, 1 defence for black against 1 d4 and 1 opening for white. Play these all the time and in all time controls so as to accumulate experience.

"Should you look for some kind of 'narrow' opening repertoire?"
++ Yes: in order of diminishing importance:
1 defence against 1 e4, 1 defence against 1 d4, 1 opening for white

"are there some 'families' of openings, which all have the same basic ideas?"
++ Yes, there are. For example with black you can play 1...g6 and 2...Bg7 against everything and with white you can open 1 g3 and 2 Bg2. As white you can always play a reverse system as if you were black.

"a bit of the spanish and italian lines" ++ Pick one and stick to it.

"Against sicilian I just respond with c3" ++ That is good

"the main ideas behind the marshall attack or the berlin (which is basically for black to decide ) are quite different."
++ Yes, that is true, but you are not forced to go all the way with the Marshall or the Berlin. Top grandmasters nowadays avoid the 26 moves long forced lines of the Marshall C89 with anti-Marshall C88 8 a4, 8 d3, 8 h3 and avoid the 20 moves long lines analysed until the endgame of the Berlin C67 with anti-Berlin C65 4 d3 or 5 Re1.

"what to do now?"
++ Do not worry about openings. You will rarely lose because of the opening, but usually because of tactical middle game errors.
Just play and analyse your lost games to learn from your mistakes.

#4

"the scandivian is a very forcing line for black"
++ the first 2 moves are, but from there white has many options.

"So that makes preparing a bit easier"
++ No, it does not: Scandinavian is still hard to play. Larsen advocated the Scandinavian as a way to reach Caro-Kann like positions while avoiding other white possibilities like the Panov-Botvinnik attack and the Advance Variation.

"would that mean such an opening is good for beginners facing experienced players?"
++ The best for beginners facing experienced players are sound sidelines.

"When i should choose the italian as white, then it's basically up to black to decide how sharp the game gets."
++ No, that is not true. If you want it sharp, then you can go for Evans Gambit 4 b4 or Greco Gambit 4 c3 & 5 d4 or Two Knights Defence with either 4 Ng5 or 4 d4. If you want it not sharp then you play d3 in both cases, like most grandmasters now play.

"The main ideas behind the two knights defence or the giuoco pianisimo couldn't be further apart from each other. And it's black who choses between the two."
++ No, that is not true. Top grandmasters nowadays replay 4 d3 to 3...Bc5 as well as to 3...Nf6. 

"I guess this is a really common 'problem'"
++ It is no problem. You worry too much about openings.
You should worry more about tactical mistakes you make.

Thank you tygxc for your thorough answer!

i opened this topic on tactics, which explains probably a bit better where I am coming from.

https://www.chess.com/forum/view/for-beginners/what-happens-before-there-is-a-tactic-in-the-position

I would be very interested in your help on that topic. 

No. While it's true many lower rated players overvalue opening prep, only playing principles will get you demolished by a prepared NM.

I try not to plug things here, but this meme of "no openings until you're an expert" actually upsets me. 

For a serious recommendation of when opening work starts to become relevant, the training program developed by GM Jesse Krai, IM Kostya Kavutskiy, and IM David Pruess recommends 1200-1300 FIDE (approx. 1400-1600 chess.com rapid) https://www.youtube.com/watch?v=nAzrdqLXy2g&t=12s 

Before that they recommend only principles.