Learning an instrument can be incredibly frustrating, but the most maddening stage is the first few months. Fingers get sore as the tips get broken in and sometime your hands just don't want to do what you tell them. While it's never easy there are a few rules to help make the break-in period a little less difficult. First and foremost, take it slow! Allow your muscles and brain to get in tune with each other. A baby has to go through many small stages to make the big leaps, learning an instrument is not different. Take time to get a solid foundation so you can continue to evolve as a musician.
Regular playing is vital to learning an instrument. I'd rather see my students sit in a quiet environment five minutes a day and have a focused practicing time than doing an hour once a week. Developing muscle memory is the key to learning and the five minutes a day is the key to getting your body to listen to your brain. The reality of life may not allow someone to play everyday, but it's a good goal.
Also, leave your instrument out so you will not only remember, but be compelled to pick it up. It could be as simple as working on a single chord, a scale, a riff or just strumming and working on timing.
Music is a gift that is a constant companion for me and I will be a student for the rest of my life. There are always new things to learn, fundamentals to be better at, and more techniques and songs to learn. It's what I love about music and also about life. I feel rewarded when I see students put things together and become musicians.