Three suggestions:
1) bees are attracted to blue flowers, so blue hyssop, borage, Pride of Madeira, etc. are good choices.
2) bees need alot of flowers, so if you have a mass of flowers, they'll be more attracted to your yard than if you have a flower here and a flower there.
3) certain flowers seem to be magnets for bees, probably because of their nectar. One example is basil. Bees swarm all over my basil with an eagerness that is absent in their behavior around neighboring flowers of other types.

Thanks for those good suggestions, thisbud4u. I did let my basil bloom last year and it got a good deal of honeybee and solitary bee traffic. Funny thing, the blossoms must not be well attached because most of the time when a bee landed on one, the tiny bloom fell off. Hyssop. Oh yes, I must get some of that! :-)
Kris

Hi thisBud4u

I noticed you mentioned in point 3 that bees are swarming all over your basil with little eagerness for the surrounding flowers. I'm noticing the same thing with my basil, except it hasn't gone to flower yet. All they do is fly around the leaves and sit on the soil! Would you know why this happens? I can understand the pollen behaviour, but not the soil!!

Cheers :)

Bees need moisture & minerals like us & can use soil for both at times. Might even be Mason bees (?) that use mud in hive & make no wax. The herb Borage has bees also attracted to it's bluish flowers & my flowering plant is covered w/ em.

Cheers, David