1. Where should I purchase my domains from? Which sites?
Domain registrants can register their domain names at virtually any domain registrar. There are many different domain registrars located throughout the world. Some registrars work primarily with the "general public” while others focus on domain management for large brands. Some of the most well known registrars off the top of my head (at least here in the US and for domain investors) include GoDaddy, Namecheap, Uniregistry, Fabulous, 101Domain, Tucows, Enom, Network Solutions, Name.com.
I would personally choose a registrar that offers the best pricing, but I would also make sure the support team is available in my country with quick response times. You can probably do additional Google and NamePros research to get third party feedback on support and pricing.
2.Is there anything I need to do with my domain before putting them on sale?
I would probably check trademark databases (USPTO Tess and Trademarkia.com for example) before trying to sell a domain name. It’s very important to avoid buying domain names with trademarks in them - especially obvious trademarks. You don’t want to start receiving cease and desist letters or legal threats since many brands monitor domain registrations and don’t mess around.
You may want to put up a “for sale” page so people who could be interested will know the domain name is for sale. Parking companies such as Sedo, Uniregistry, Voodoo, Bodis, ParkingCrew, SmartName…etc… have different versions of parked pages which offer that in addition to their PPC parking links. You can also use a company like Efty to put up for sale pages, or you can put up your own "for sale" landing pages that you create. You can also do a little of everything.
3.Which marketplace would be best for selling for beginners? Flippa, Godaddy etc.
Really depends. Many people like to list domain names at several marketplaces. The important caveat is that if you have “buy it now” pricing at multiple venues, you need to be sure to take down listings of sold domain names so they aren’t sold in multiple venues creating a problem for you. Sedo and Afternic likely have the biggest reach to end user buyers (ie companies/startups) that want to buy domain names through the domain registrar channel. For instance, if you own 123Widgets.com and have it listed for sale on Afternic, if a buyer tries to register that domain name at GoDaddy, your for sale listing should show up in the registration path. I would first learn what domain names are selling and for how much before worrying about selling them. Also, don't just look at the big sales. Most of those are domain names that were registered many years ago and would likely not be good comparable sales for newly registered domain names. NameBio archives many public sales - even smaller ones - so that would be a good resource to learn about domain name sales.
4.Should I consider getting help of a broker or just put my domains in the marketplace directly?
I can't imagine that any domain broker is going to take on newly registered domain names under brokerage. Most brokers won’t even take on decent or good domain names. The better and best brokers want the highest value names because it can take considerable effort to sell any domain name, and there is not enough commission in it for them to take on lower value domain names. Unless you are buying domain names for big money on the aftermarket, I don't think brokers will even consider names.
5.How am I supposed to determine my domains value? Suppose, I am feeling like my domain name worths $1000 but I can't be sure about that guess of mine right? So, how could I verify about my domains price, who could help me to give some advise about the price?
Not any easy answers and not something that is easy to learn without spending a lot of time analyzing the market. I price my name based on the knowledge I have gained following the market. That said, you can use a resource like NameBio to find public comparable sales using the keywords from the domain names you own. This can give you a decent idea.
The short answer is that random domain names you register today will likely not be worth very much money.
6.Can I just go buy a domain and put it on sale right away or do I need to wait for a certain period of time?
Yes, but domain names can not be transferred to a different domain registrar within 60 days of being registered (an ICANN regulation). Most registrars, I believe, allow inner registrar transfers. For instance, if you register a domain name today at GoDaddy and agree to a sale in 3 weeks, you can push it to another GoDaddy account. However, if a buyer would want to transfer it to Network Solutions, that is not permitted for 60 days.
7.How do I complete the transaction once I find a buyer to sale and complete my deal?
If you sell a name privately, you can use an escrow service like Escrow.com. If you sell via a marketplace like Sedo or GoDaddy/Afternic, they will provide instructions. I am sure you can do a Google search to learn about the escrow process.
8.If there there are successful brokers in this community then please let me know so I could PM them about my domains and get some advise about the price. If they thinks my price is fit for brokers then I could take their help to sale some.
It’s not about your price that really matters. It’s really about their valuation. If you don’t have relevant one or maybe two word .com domain names (or 2/3 letter .coms), most brokers won’t have any interest in working on the names. It’s simply not worth their time since there are so many good names. Even if you think your name is worth $500,000, a broker is not going to work with you if they think it is worth $2,000 because there is not enough in it for them and they won’t want to work with someone who has ridiculous ideas about their domain name values.
There is a lot of good information on NamePros and on other domain investing related websites. The info above is just my opinion based on a quick look at your questions without knowing anything about your background or domain names you may own. For the sake of answering your questions quickly, I assumed you are simply hand registering (or plan to) domain names. It would probably be helpful to spend time reading various threads on NamePros and searching Google for your questions. My bet is you will find quite a bit more information from people with different experiences around the world. Be mindful that many things have changed over the years, so advice shared in 2008, 2012, 2015, and even last year may no longer be valid or helpful. This is an evolving business.
There are a lot of sharks in this business, so be mindful of any advice or assistance given or offered by anyone - whether it is given to you specifically or in various threads. There are plenty of helpful people, too, but it can be hard to tell who is offering a hand and who wants to take advantage of a new domain investor.
Domain investing is not easy, although there is a bit more leeway for someone with a big bankroll who buys blue chip domain names. Many people who start out in domain investing lose their investment.
Good luck on your domain investing journey. It can be a tough business, but it can also be lucrative if you figure out a way that works for you and your goals.
Just FYI, I operate a domain investing website (DomainInvesting.com) in addition to my domain investment business, but I do not offer any type of consulting, brokerage, or other services in any way, shape, or form.