I've found the HubSpot Sales blog to be surprisingly good. It can get a little "spammy" feel at times but I got a lot of good advice overall. I don't know how

I've found the HubSpot Sales blog to be surprisingly good. It can get a little "spammy" feel at times but I got a lot of good advice overall. I don't know how their marketing blog is - never tried it but you could check it out.