Just hang in there, you'll start getting better at it. Honestly, it took me probably two months to finish my first 10 wins. Partly because I didn't battle very often. I'd jump in for a game or two here and there when I was really bored or something. But I never actually stayed for more than 3 or 4 games in a row. My win percentage is probably crap because I think I lost my first 5 games. Then I got to where I could win about 45% of them. I went on a tear to finish it off this week, winning 4 in a row.
I started out with a team I found on here - Singing Sunflower
/ Blossoming Ancient
/ Ruby Droplet
Sure, it wasn't "my original idea", but I liked the pets because the tree and flower looked cool. The Droplet just worked well with them. I liked this team because it wasn't the typical "Valk / DAH" combo, plus it gave me a way to easily control the weather. And I was able to grind some wins out of this team, so it wasn't all bad. It is however, a very long game plan, and annoys the crap out of a lot of players.
I have since moved on to some teams I made after seeing them being used against me. So none of my teams are original, but they work. Some of them are less successful than others. But for the most part, I enjoy playing them because they do interesting stuff. And none of my teams are super hard to get pets, like the Treasure Goblin
, or Murkalot
. I simply don't have the money to spend on those types of pets.
My point is, hang in there, it can be done with some rather easy to get pets. And don't get discouraged, it'll come in time. And like others have said, find the times when more people are on because it will bring a wider variety of opponents/skill level. You'll know those times because the queue will be SUPER fast! If you find the queue to be very long, that's a low pop time, try another time. And if you go on a losing streak, just come back another day. You'll be surprised how things chance from day to day. Also, keep in mind, a 50% win percentage is actually pretty good. So don't shoot to win them all, it'll help you keep some sanity.