I bought my first guitar for my 16th birthday. It was an old second-hand hollow-body electric with one pickup. I bought it because it was the most playable guitar I could afford.

I played that thing like an obsessed lunatic, thumping away at it every chance I could. I have vivid memories of callouses on my fingertips with blood-blisters under the callouses!

You don't have to be that fanatical about it. Pick one thing, (like changing smoothly from D to G while strumming), and keep at it until you can nail it every time. Then start to add more things, one at a time, until you have a practice routine that you can use for a warm-up exercise.

Good Luck.
L