It sounds simple. Just try. Every day, day in and day out. Whatever you've set your mind to doing—starting a garden, writing a novel, organizing a charity event—just try, and be consistent in your efforts. You don't have to be perfect. The reason the notion of "just trying" is so important is because most people don't. At least, most people are not trying to do what you're trying to do. And if they are giving it a go, most won't stick with it.
So you have to stick with it. That's the key. And also don't go through the motions: really try. I used to teach English to adults, and that was the biggest criterion that separated "A" students from "F" students: is this person trying? Rare was the student who came into the class knowing how to write at the college level. Most started at ground level.
I once gave an "A" to a guy from another country who couldn't string two sentences together without shredding the language. His ideas would start out great, then quickly disintegrate into a jumble. At least in the beginning. But he came in a few times before class for one-on-one help, he emailed me outside of class if he had any questions, he visited the school's writing lab, and he always came to class ready to participate, showing that he'd read the material. And his writing improved a little. Not a lot, but a little. And he walked out of my class with an "A".
Grades are subjective things and not at all a good judge of someone's intelligence. But a big component of intelligence and a great indicator of future success is if someone gives a damn. If they make a commitment and see that commitment through to the end.
That being said, you also have to recognize when to give yourself a break. If you don't feel 100% up to the challenge on a given day, don't berate yourself and get frustrated and quit. Quitting doesn't make you dumb, but it will make you unsuccessful. And no one wants you to be unsuccessful (all right, maybe there's some jerk out there who doesn't want you to be successful, but they're an idiot and you should ignore them).
All this is to say what Woody Allen said so succinctly: 90% of life is just showing up. In other words, if you just show up, if you show you give a damn, that's a great start. The other 10% is where the wheat is separated from the chaff. But you have no wheat—heck, you don't even have chaff (whatever that is)—if you don't show up.
Me? I write one hour every day. And for that hour I try to stay completely focused on writing the best hour's worth of writing that I can. Some days I'd rather do anything other than write. But I force myself to write anyway, and you know what? Those are usually the most rewarding writing days once I'm done. I know that writing only one hour per day is not ideal, but it's all I can manage in my hectic life, so I make the most of it. Some people would look at one hour and say, "That's not nearly enough time to write something great," and they'd give up. But I choose to see it as an opportunity. Yeah, it might take me longer to finish my novel, but I'm determined to write it and I'm going to make it happen.
Be as good as you can possibly be, but also realize that no one is perfect and be kind to yourself. You can do it. So do it!