Well... no. I did play WarMachine when it came out but I don't know that any of my advice is really applicable anymore.
I played Cygnar and liked Warjacks much more than infantry and I had a rather mecha-heavy list with fun units like the Journeyman Warcaster (coolest solo in the game, IMO) and a Field Mechanik and his gobbers. I used Stryker as my Warcaster but always considered switching to Haley. That was before Escalation came out, and I assume things are pretty different now with all the new options.
I don't know if people still use the "Prime" book anymore but it had a tactics section in the back for each faction, which was pretty good for a beginner.
Generic advice that's probably still good:
- Your choice of Warcaster is critical. Choose one that works for your play style and learn to use his or her feat well.
- Always understand what your opponent's Warcaster feat is and what it can do! (Or you can learn it the hard way all of a sudden. Ouch!)
- Spell lists are important to understand as well. Your own and your enemy's.
- Combined arms forces with at least a few Warjacks are generally better than very lop-sided forces. That's the designers' intent anyway, though no-Jack forces were pretty popular for a while there.
"Every man is guilty of all the good he did not do." - Voltaire
"It is to be expected that we will run out of fossil fuels before we run out of optimists, who are, along with fools and madmen, a renewable resource." - Dmitry Orlov