In my soldering experience there are three key elements: The quality of the solder, the thickness of the solder and the iron you are using. For a beginner, 37/63 is a good leaded solder and buy it in .5mm or .7mm ( I have it in sizes from .1mm - 1mm, the thinner the quicker you need to feed, but the lower temperature and more control you have over the amount of solder you are using). I use a metal scouring pad in a small metal box to clean the tip between applications and have a thin tip with a slightly flattened end for most PCB work, like the third tip from the right in this pic: http://image.dhgate.com/albu_263532956_00-1.0x0/hakko-900m-t-b-soldering-iron-tip-fit-for.jpg
The other useful tip for general work is the fourth from the end - a happy medium between flat tip and ball-end.
Hardware store solder is usually rubbish.
I use a pot of flux as well as a flux pen - if I have a lot of fluxing to do, I use the pot, if it’s just a dab, the pens are great. Make sure the flux suits the solder - don’t use lead-free flux with leaded solder, for example
Practice is the key - there are some great instructional videos on youtube:
EEVBlog have a great three-part intro to soldering, including the tools, solder and flux - well worth a look even for the experienced:
Part 1
Part 2
Part 3