Weeds such as dandelions and daisies can be removed with a root weeder or an old kitchen knife. If you are persistent, you can remove a lot of weeds from your garden using mechanical means. If you are particularly concerned, you can also use an herbicide to remove lawn weeds.
If a lawn has weeds all over it, it means that the weeds have overcome the grass seeds because the conditions were more favourable for their growth. You have a major problem with your lawn. The soil may be compacted (indicated by the presence of common plantain), greasy and damp (daisies and dandelions), very poor (white clover), or too acidic (moss). You should then consider removing these areas completely, creating a soil structure which is more beneficial to lawns, and resowing the whole area or covering it with rolled turf.
However, we advise that you consult a local landscape gardener, because it is hard to professionally assess a surface without studying it in detail. Tip: Especially in serious cases and for larger lawns, do not use just any landscape gardener. Choose one who has extensive experience in laying lawns - such as a golf course specialist - instead of someone who simply knows how to lay natural stone walls and create swimming ponds.