well, first let me welcome you to last.fm. hopefully this article will help you to make the most of your artist experience here @ last.fm. *if you are looking for someone else to manage your artist profile here at last.fm, please see the footer of this journal article.
if you haven't already, sign up here. if you have found your band already on last.fm and would like to claim the account, please do so by going to this link and searching/registering for that artist.
if you have any trouble doing so, or with anything related to your artist account even after you sign up, you can check the label services forum. if you are already a music manager you can also check the music manager faq.
now, on to the good stuff...
start uploading some tracks for people to listen to/preview. personally, i make all my tracks available for free to listen to and download in full - but the choice is yours of course. i would recommend having a few full length previews available if possible - and add a few as "featured tracks" as well. you can upload the album art on the same page where you upload the tracks. make sure the files are named and tagged properly and that they are also encoded properly as suggested in the faq. after you get some tracks uploaded, start to scrobble them from your "home library" (listen to them in your media player of choice) to start to get some stats to appear....but dont go and start advertising yourself everywhere just yet....keep reading ;)
to upload some artist photos, go to your artist image page (for example: my artist image page) and click on the "upload picture" button at the top of the page. you will be redirected to browse for the picture to upload. once completed, you can edit the title/description/etc as desired. remember, if you put your artist name and a brief description in the title, it increases your seo (this is also true on your other website(s) ;) ).
*to upload a single artist image that will be used as the main image no matter how the users vote, do so from the "music manager->manage catalogue" page. click "change the artist image."
add a bio/wiki for your artist by navigating to that page (for example: my artist wiki) and if no wiki exists yet, it will say something like "We don’t have a description for this artist yet, care to help?" - click on the "care to help" part and add your artist wiki info. if the wiki does exist already, you can edit it accordingly. remember to write it in an illeist format.
have a youtube account/channel? if you have music videos for your tracks uploaded there, you can connect them to your track pages on last.fm by going to the webpage for the track - you will see "Know about a video for this track? Help build Last.fm by adding it." click on "adding it" and a pop up will appear. paste in the *short url and click "add video." you can do this for all tracks you have video for.
*by "short" i mean the actual url of the video, not http://www.youtube.com/watch?v=rm32MFFturk&feature=related for example.
add some global tags to your artist. try to use genres as tags to start out with, since those who listen to the general tag radios will then encounter some of your songs while they listen to the station. i also recommend joining the "central point" group and following the instructions there.
add a news feed for your artist. let the fans know whats going on if you can. blogspot or your myspace blog are a few of the great ways ive found to do so. to get them connected to your artist page, go to the "music manager->artist news" page and paste the url of the rss feed you wish to add and click "find", then last.fm should take care of the rest. i believe you can have multiple sources (i personally only have one - blogspot).
to get journals to appear in your artist profile sidebar, you (or any user) just has to include the "(artist)Artist Name Here(/artist)" tags in their journal article.
*replace "(" and ")" with "[" and "]" or see bbcode instructions here for further usage options.
similar artists will start to appear for your artist as you and other listeners scrobble your music in succession with other music. you can visit the faq article in the music manager for more about this as well as some other helpful tips found here on the label service forum article of the same nature. im writing this journal article from my experience as a user/artist here on last.fm in hopes that it might help you as well.
put a link in your signature (from your user settings panel) and join in the fun all around last.fm forums, groups, games and more to expose your link(s) to the millions of listeners here @ last.fm. also, be sure to check out the aforementioned "central point group."
hope your experiences here @ last.fm as an artist and a user are the best possible in all regards; and thanks for joining!
if you are looking for someone to manage your artist account, please contact me via private message through last.fm or email at email@example.com
i am also a programmer/developer and may be able to offer you some options, ideas, graphics, code, features, management (of web related maintenance) , services and more for your your other website(s) as well - contact for details.
(will add some screenshots soon as visual aid)