I am not really a pro player but here are some of the things that I have learned so far during play ..
Think before you reload ! Just like every other "noob" out there in the beginning I made the mistake of reloading immediately after shooting someone or too soon so many times and got shot in the face while standing there helpless , desperately waiting for the reload to complete! Later on I learnt to quickly switch to a different weapon but even then the pros took me out before I had a chance!
Always remember to only to reload if you are sure you are in safe place and even then think twice whether you need to reload
Also try and get a headphone and mic ASAP if you do not already have one as its very important to fully enjoy and experience the game and in being a good player! The headphones are absolutely vital for you to hear the footsteps of your enemies and the better ones should allow you to pin-point the direction as well giving you a big advantage! Though as most players these days do have one, you will at least be in a level playing field!
You would absolutely need a mic so you can effectively communicate with your teammates and make friends. I know the struggle when you don't have a mic or a good one and you have to shout over the inbuilt mic to get your message across! Also no one likes it when you scream over your laptops microphone with static and all kinds of noise! And if you do have a good mic, please do not mic spam! For example you die at B and observed the bomb is also there with two terrorists, then just say " 2 terrorists in B with the bomb" .If you notice what guns they are carrying you can mention that too , say " 1 ak and 1 awp " . Usually what we see newbies do is shout on top of their voice "BBBBBBBBBBBBBBB!!! B B B B B B GO TO B !! " That is one of the worst things you could do as didn't provide any info and you are voice spamming your team .
Plus from my experience with the mic you would be able to make more friends and then you would not find yourself soloing the queue always . This is also something to consider as the CSGO community is big and you will meet lots of nice people but to be honest there are also a lot of trolls, haters, hackers and other toxic people you will have to play with when you are soloing when instead you could be playing with people that you can actually depend on as a teammate
The other thing is when you do die and you will a lot , you would have to spend your time watching others, make use of this time and learn from the better players out there.
Finally if you really want to get better there are lots of maps that can help you practice your aim and shooting that you can find in the workshop along with a number of other fun modded stuff
As for map tactics, I usually keep my attack plans simple, for example on my favorite map DUST 2 , I usually plan a mid smoke and then we split both short and long to enter at the same time.
I really love this game and cannot count the number of hours I had spent playing it since my childhood
My Gamer ID is 10479688