how can i tell the difference between weeds and good plants?

I am trying to weed my flower beds and i can't tell what i should pull out. is there a way to recognise weeds or do you just have to know?

Answers:
i don't know but i do know this- it'll be those pesky trolls being evil again and making your garden overgrow...bwah ha ha ha.....

Other answers:
A weed is a plant where you don't want it !
A weed is a plant where you don't want it !
You can't smoke good plants
Weeds are just plants growing in the wrong place. If you like the look of the plant leave it where it is, if you don't, weed it out!
If in doubt, pull it! You only want desirable plants anyway.
buy some weed killer that will only kill the weeds
I learned by looking in my neighbours unkept garden or patches of derelicts ground and seeing what leaves where attached to small plants I didnt like ie dandelions. then when I started growing my own seedlins I recognised the seeds leaves as good thus distinqueshing the bad. You have to start to look at picutes and plants in order to start recognising them. Bit like anything new.
If you like it keep it. Weeds are flowers out of place.
dont listen to zeuse, you need a good wild flower book which should have all the weeds in it, if not why not get a gardener round to give you advise on your garden and maybe a little help. Lets hope if you do its not zeuse. P.s i now know weeds because of experience, but it took pulling up a patch full of bidens before i got there.
  • Why some trees smell like sperm????
  • how do i get my rocks out of my yard without digging them up. I need my yard it needs grass.?
  • How do you keep your cats from using you inside tropical plants as litter box, plant is 6'2 at least?
  • When is best time to trim Arizona queen palms with green and brown fronds?
  • How do you keep zucchinis from getting blossom end rot?
  • how do i get rid of snakes?
  • Getting rid of bracken?
  • My globe willow is bubbling sap from the trunk, is something wrong with it?
  • PA state tree/state flower?