Since you want to promote your business on the forum then buying copper membership is one of the best way to help establish some reputation for you because nobody trusts newbies easily and you can post images without any junior member restrictions also.

As @dkbit98 and @DdmrDdmr has already pointed out you some ways like of avatar and signature clarity along with advertising on the forum ad space so you can check both of them for clarity.

You can hire some campaign manager who can take care of signature campaign along with the promotion on the forum which is best way or bounty program if you wish to do so but if you say ranking up yourself that will not help in promotion of your business as you could join some campaign on full member rank but I suppose you are not into that.So you can checkout this thread by @Hhampuz who is managing many campaign on the forum and can help you out :

Hhampuz Campaign Management, Escrow Service & Promotions | Available Now!

Or the round 350 which is active by @theymos you can go that way.