So on my iPhone I've been playing a lot of Battle for Wesnoth in my spare minutes. It has lots of campaigns and I like the style of game, turn based hex based unit strategy, a lot like Panzer General and Panzer General II which I loved to death in the '90s.
The main campaign, Heir to the Throne frustrated me a lot when I first started playing. One scenario crashed the game every half turn so I had to save every minute to not lose a lot of progress (this was fixed with the latest free update, game is far more stable now and rarely crashes) and I reached another scenario where I could not win. Just could not beat the mission. I tried like ten times before I stopped playing and went back to other games for a while.
But then I came back, tried some other smaller campaigns, and then finally started the main campaign over again. I asked myself, why am I dying so badly in that mission? What am I doing wrong? Well, for starters the enemy hits hard with his attacks and my small but elite forces were getting chewed up. Every unit killed or wounded to near death left the rest that much more vulnerable. I realized I needed more cannon fodder to take the enemy charges so I could counter charge with my veteran units and then follow up with yet more cannon fodder to take the ground.
The problem was I didn't have enough gold to recall my veterans as well as recruit newbs to throw into the grinder. Until I realized there was no penalty to going into debt with the gold and making the money back through taking villages for income later in the mission or getting the early finish bonus.
With this change in tact I found I had a lot more success and not only got through the stumbling block mission, but defeated it on the first try in my new run through. With that momentum I completed the rest of the campaign successfully (25 missions) and have moved on to other campaigns, some long, some short.
Moral of the story? Sometimes you are just doing it wrong and you can't tell until you are 7 missions in.
(I was going to post a bunch of Eve screenshots but left them at home. Oh well.)