best opening for semi intermediate level

please suggest

Openings are a personal choice.  

1. f3 and 2. g4

The simplest advice is often the best advice.

When I coached 700-1400 OTB regular rated players, I found the best openings were those that led to the most easily understandable middle game plans.  ANY opening works if you know where you're going with it - so don't choose the opening based simply on getting pieces developed, but on being able to figure out what those pieces might do after you're fully developed.

For 1 e4 as White, against 1...e5 I like the Bishop's Opening 2 Bc4 then usually 3 d3 4 Nc3 and 5 f4 (which can also transpose from the Vienna Game as 2 Nc3 3 Bc4 4 d3 5 f4).  From there your opponent usually castles O-O, and you then want to castle O-O-O, Pawn Storm with your f, g, and h pawns, backing them up with both Rooks.  You can often play an early f5 and that blocks most of Black's pieces from the K-side while you aim all the pieces you practically can at Black's K and relentlessly attack before he gets a chance to organize a Q-side attack.

The Bishop's opening can also be transposed into the Vienna Game or King's Gambit Declined: but where you can get wild openings out of those latter two so, at the 1400 level, I like the Bishop's Opening order: it usually forces things to go in the pattern you as White want.  Additionally, most players aren't familiar with the Bishop's Opening's order of moves.

Here are a couple of games - transposing from the Vienna Game but with the same first five moves I listed above - that show 1) how powerful the opening is if Black makes just one mistake and 2) how a K-side Pawn Storm naturally develops from the opening.

Note also that I keep trying to get all my pieces involved in attacking the Black King and try to keep my opponent from getting all his pieces coordinated.

This Vienna/Bishop's Transposition shows a K-side Pawn Storm naturally develops from the opening:

thanks

I highly recommend to look into two opening repertoire books by Vincent Moret.  The repertoires focus mainly on aggressive but sound lines for which understanding the typical plans and strategies are more important than memorization of myriad lines and variations....

My First Chess Opening Repertoire for White....

https://www.amazon.com/First-Chess-Opening-Repertoire-White/dp/9056916335/ref=sr_1_3?s=books&ie=UTF8&qid=1515364956&sr=1-3&keywords=vincent+more

My First Chess Opening Repertoire for Black...

https://www.amazon.com/First-Chess-Opening-Repertoire-Ready/dp/9056917463/ref=sr_1_1?s=books&ie=UTF8&qid=1515364956&sr=1-1&keywords=vincent+moret

Introduction to Moret's White repertoire...

https://www.newinchess.com/media/wysiwyg/product_pdf/9033.pdf

Introduction to Moret's Black Repertoire...

https://www.newinchess.com/media/wysiwyg/product_pdf/9050.pdf

See my mini review of Moret's White opening repertoire book here....

Good Chess Openings Books for Beginners and Beyond...

https://www.chess.com/blog/RussBell/good-chess-openings-books-for-beginners-and-beyond

More on Moret's White repertoire...

https://www.youtube.com/watch?v=f41ZbPq9OpE

https://www.chessable.com/opening-book/my-first-chess-opening-repertoire/7543/

Some more opening repertoire suggestions by IM Andrew Martin and GM Nigel Davies....click on their respective names at the top of the web page...

http://www.chesspublishing.com/content/repert.htm

Finally, the following articles relating to choosing an opening repertoire offer food for thought...

http://www.mark-weeks.com/aboutcom/aa02i07.htm

A three-part set of articles by GrandPatzerChess - Parts 1 & 2 are concerned with his thoughts on building a White repertoire.  Part 3 with a Black repertoire.  I found the articles on the White repertoire to be somewhat confusing and even contradictory in places.  Part 3 on the Black repertoire seems to be a little more coherent.  Nevertheless I found the articles to be generally interesting and thought provoking...

http://grandpatzerchess.blogspot.com/2007/03/openings-for-improving-players-part-1.html

http://grandpatzerchess.blogspot.com/2007/03/openings-for-improving-players-part-2.html

http://grandpatzerchess.blogspot.com/2007/03/openings-for-improving-players-part-3.html

1.c4 best by test

Possibly of interest:
My First Chess Opening Repertoire for White by Vincent Moret
https://www.newinchess.com/media/wysiwyg/product_pdf/9033.pdf
https://www.chess.com/article/view/how-to-understand-openings
A SIMPLE CHESS OPENING REPERTOIRE FOR WHITE by Sam Collins
http://www.gambitbooks.com/pdfs/A_Simple_Chess_Opening_Repertoire_for_White.pdf
http://www.jeremysilman.com/shop/pc/A-Simple-Chess-Opening-Repertoire-for-White-76p3916.htm
Playing 1.e4 - Caro-Kann, 1...e5 and Minor Lines by John Shaw
http://www.qualitychess.co.uk/ebooks/Playing1e4CaroKannandothers-excerpt.pdf
A Chess Opening Repertoire for Blitz and Rapid by Evgeny Sveshnikov and Vladimir Sveshnikov
https://www.newinchess.com/media/wysiwyg/product_pdf/9020.pdf