Picking up a musical instrument was the most exciting thing going on in my life at the age of 7, and now at the age of 16, I still love picking up my violin and being able to play. Since 7, I have also picked up other instruments, like the piano, ukulele, etc. There are lots of people who sort of think about playing an instrument and 'dabble' in doing so, but very few stick at it. If you are looking to start playing an instrument, then here are some tips:
1) Buy a decent instrument.
Don't bother buying a £10 uke, or guitar. If you really want to learn, your going to have to splash out a little. For example, my uke (a tanglewood that you can buy here) cost me £50, but I got a lot for my money. (To read my review of my uke, click here).
2) Make a habit of practising.
Making practise a habit means that it won't feel like a chore, eventually. The first few weeks are the hardest as the habit takes some time to develop, but just stick at it.
3) Look into the possibility if lessons
Okay, so maybe you don't want to pay for lessons because you have made the assumption that they will be expensive, but just look into it. Sometimes lessons can be reasonably cheap. Don't only look with private tutors. Some music shops will offer lessons for an incredibly reasonable price.
4) Pick something that you want to learn to play
This will really help as it will give you a goal. If you start to learn piano but don't really have a goal piece, chances are that you won't stick at it. If you pick, say, fur elise, you may be more likely to keep playing until you can play that piece.
5) Pick decent songs to learn the instrument
I think a lot of the time the biggest issues with someone who wants to play an instrument is that they think it will be ages until they can play anything of substance. However, in music, lots of songs use only 4 chords. This means that with 4 chords, you'll be able to play some pretty decent stuff.
These are my tips. Give it a try and let me know how it goes in the comments