Secret to winning pub games?

I have played only pub games so far and by and far the best way to win is simply communicate with your team. Not trash talk, not flamming, give advice, congrat, etc. Its a simple idea and it destroys the other team. Why play pub if you will refuse to communicate at all???

Communication is important, but you can get by without it as long as you're all around the same level of play and have similar expectations of each other.

Communication becomes an issue when you have very complicated plans (e.g. like pro teams in pro games) or there are large skill gaps. 

Example: last night I queued with some friends who are about 1k MMR lower than me and I wound up on support. The entire game, I had to tell our carry Mirana how to position so that she could immediately follow up with arrows after I stunned as Wraith King (since there was a small window of time for her to land arrows). Had I not, she would have sat behind the creep wave and never been in position to arrow.

The main things I find are:

1) Play Well

Not really a secret. But just keep getting better and watching for little things.
For instance:

• After you initiate a gank, rotate around the target to block off ideal escape paths -- try to surround them, or force them to route to something non-ideal. Otherwise, they face getting blocked (i.e. basically setting picks or body-blocks to give the DPS hero more time to just hit them)
• Don't be visible if you don't have to -- deny information
• Always be farming or doing something
• Switch Power Treads to AGI before using bottle

If you had a rough game, watch the replay. If you need inspiration, find high tier pubs (not pro games) and watch ones that are just starting. This is because you're not playing with a 5 stack, so the playstyle of a pro game will not help you as much as watching a pub. You will learn from both, but pubs have more 1:1 with your MM experience.

2) Pick Someone You Can Make a Difference With

You may be able to play a lot of heroes, but they cannot all be your signature hero. There is a HUGE difference in knowing a hero and having a signature hero.
Example: You may know that offlane Faceless Void builds 3-1-1, gets Power Treads + Mask of Madness + Maelstrom. However, do you know that you Time Walk onto an enemy and hit them a few times before casting Chronosphere ? This is because you want to make use of the attack and move speed slow that happens when you land  Time Walk.

You'll see many pro players have stretches in their dotabuffs where they just spam a hero. Play them over and over. Learn their hit animation, when to make slight build changes, get a feel for how much farm you should be at, know how to play against various matchups (e.g. how to not feed as Tidehunter vs. Razor in 1v1 offlane).

3) Keep Morale High

Try to:

• Keep vibes positive and fun
• Keep the team focused -- it takes attention away from negative thoughts
• Remind people that they want to win and want their MMR to go up
• Get others to turn criticism to constructive criticism
  • e.g. get the guy saying "stop feeding" to say something more like "don't overextend" or "don't ward alone" (note: ward when your team is doing something so it blends in with activities rather than sticking out on its own)
• Defend those who are getting ripped on for just having a bad game (unless they are assholes)
  • Getting flamed by teammates is frustrating --> now that player is playing even worse --> if you have one asshole on the team, don't let them bring down another player so it effectively becomes a 3v5

You have to help get people out of this mindset that "we're not stomping 50-2 at 10 minutes, welp gg". The vast majority of players are terrible at figuring out how the match will play out. They don't see many moves ahead.

Plenty of lineups look like they are terrible in the laning phase, but really come together mid game or even turtle to late game and crush. Never give up because there is always a chance the other team will make a mistake -- and it's a very high chance. This is pubs, not pro.

4) Pick Things That Make Sense

After everything else, try to make a pick that works.
You can often get away with greedy lineups in pubs, so don't worry too much about that. Most pubs go to 50 minutes regardless, so greed isn't heavily punished.
You can counter-pick to some extent, but make sure it flows with your team as well.

For instance, I played a game last night where the other team had some heavy push (i.e. Lycanthrope, Nature's Prophet) and our team was mana heavy. Normally, I'd pick up something like Bane against a hero like Lycanthrope. But, given our team (i.e. Storm Spirit, Q/W Invoker) I went with Crystal Maiden . She has Frostbite to keep Lycanthrope in place pre-Black King Bar. But more importantly:

• She feeds Storm and Q/W Invoker mana, which they need
• She is very strong early game -- and Storm Spirit needs a team that can get ahead and stay ahead to be effective (also, had a Visage supporting with me, who is a hero that loves to be aggro early on - so the pairing made sense)
• She has a good amount of AoE to deter pushes
• She can roam fairly effectively, or jungle depending on what is needed

I'd also say don't be afraid to pick the "OP" heroes. If you want to win, pick what will win.