If you are feeling ambitious, you can link each of your domain names to its matching “buy it now” purchase page at one of the marketplaces. Another more sophisticated option would be to “park” your domain with one of the leading domain parking companies, such as DomainSponsor or SmartName and enable their built-in “for sale” message and contact mechanisms.
Your course of action really depends on how much work and effort you can put into the expired domain. If you're barely able to maintain and optimize your current site, you probably want to just 301 redirect the old site (note: see my amended comment above about the link value not likely to be passed). If, however, you're more creative and have some time on your hands, you can try your hand at crafting a microsite. If you really know your stuff and are experienced at making money off various websites, you'd probably do well with the third option.
I have a question regarding a certain keyword though generic but it is trademarked and the trademark owner asked me to remove the parking page, is there a way i can offer my domain name to the company? What is the best approach in selling the domain to him without hard selling it and giving a reasonable price. I will be giving 10% commision to any domainer-mate that can help me pull the sale off.
1) pending delete auctions.  These are domains that were not renewed and are going through a pretty complicated drop process.  You can backorder these names at the auction venues and then each attempts to "catch" the dropping domain.  If one is successful you win the domain at $59 if you're the only one to backorder the name.  If more than one person backordered the domain a 3 day private auction is held.  Once the domain goes through the drop process, the back links have pretty much zero SEO benifit to the new domain owner.
Domain names expire when someone decides to stop renewing it. They may not be available to register immediately. We update the search index every night, so some names may already be renewed or re-registered. Some may become available in a few days. Some registrars, like GoDaddy, will let you buy a name that one of their own customers expire immediately. When you find a name you like, just click on it to try backordering the name!
Since the Buyer pays Escrow.com and not the Seller, Escrow.com can withhold payment until we're satisfied the domain name has been transferred by the Seller. One of the ways Escrow.com does this is by checking the WHOIS database of the appropriate Registrar to make certain it properly reflects the new Buyer's name as the domain name Registrant. Once this has been verified, Escrow.com releases payment to the Seller.
Domain name expert Bill Sweetman has provided strategic domain name advice to major companies around the world for over 20 years. Bill is the President & Lead Ninja of Name Ninja, a boutique domain name consulting firm that helps companies acquire, manage, protect, and profit from their domain names. A self-confessed domain name fanatic, Bill registered his very first domain in 1994 (which he later sold for five figures) and has been perfecting his “Domain Karate” moves ever since.
Here's an old post on search engine roundtable that claims google's policy is to discount previous backlink juice when a domain changes ownership.  I'm not convinced whether this is actually true or something Google says to discourage excessive domain buying / 301 redirecting for SEO benefit.  The comments above seem to give varying opinions on this matter. Would be great to get to the bottom of that one!
All very relevant points for anyone wanting to sell a domain name. Sometimes it is the basic points that we need to be reminded of in a transaction like this. What is the potential of selling a .com domain that has a relevant search term to a particular industry, but hasn’t been used on a website yet? So it is a good search term but no current traffic.
Domains that are indexed on Google and highly ranked are particularly attractive to traders. Other SEO aspects, such as backlink profiles or the search volume of the keywords in domain names, also play a significant role in appraising value. Design can also positively affect the price of a domain. Short and succinct names that are easy to remember are especially advantageous. Endings are further factors that should be taken into account. Top-level domains (TLDs) such as .com or .org are by far the most sought-after endings.

That said, my recommended budget for beginners would be $500+. Using this budget you could buy a bunch of high-potential $10 domain names, expired/dropped domain names or a mix of both. It’s very important to invest only what you can afford to lose and treat this as a side hustle till you get the momentum going. As you gain experience, industry expertise and some sales under your belt, you can then consider slowly growing your business into a full-time gig.