The Rarible interface is pretty easy to use, but I did find some "bugs" during my learning effort today.  I though I would pass the info. along to try and save other hobbyists and artists some time and funds if possible.

1.  Before completing the process to convert your content into an NFT, make sure you understand what gas prices are and the risk you take in the process.  Business Insider has a pretty good article that can explain some of the potential downsides at https://www.businessinsider.com/nft-investing-crypto-art-what-is-a-gas-fee-explained-2021-3?op=1

    I think there are plenty of upsides to NFTs and am a big fan of the new artist space for this, but I think it's important to go into the process with the understanding that you will pay up front for some of the upside potential.

2.  Creating via ERC-721 vice RARI may be a good tailored, long-term decision, but the gas is higher for ERC-721.  For more info. on why ERC-721 may be better in the long term, see https://www.reddit.com/r/NFT/comments/m6iq84/some_explanation_on_making_an_erc721_collection/

3.  As a novice, I found Rarible.com pretty easy to use, but I did get hung up at the interface between Rarible.com and the Rainbow app when it was time to pay for my transaction.

     As a first timer, the process of executing a transaction wasn't completely transparent to me.  I found it simple to create a new collectible.  I did choose to use an ERC-721 vice RARI collection, which brought up an additional popup to create the ERC-721 collection.  Once that was complete, I was stuck for a bit trying to figure out why the "Follow Steps" popup showed a "Deploy contract" option that was spooling, with "In Progress" listed in a greyed out box.  At first I tried the sit-and-wait technique, but that didn't work.  Eventually, I realized that the transaction was pending my approval in Rainbow (which depended on me choosing an amount of gas I was willing to pay).  I was a bit confounded why there was no popup or notification on either Rarible.com or the Rainbow app.

     Once I realized the transaction was pending my approval in Rainbow, I found the provided gas options to be somewhat high for what I was trying to do.  (This is the part where you effectively decide how much speed you're willing to pay for in terms of gas prices.) 

4.  Along the lines of #3, it helps to do some research on current gas prices before confirming the final transaction in your wallet.  ETH Gas Station | Consumer oriented metrics for the Ethereum gas market was helpful for me today to develop baseline knowledge in order to select an option in Rainbow (the wallet app I chose to use for this experiment) for how much GWEI (units of Ether gas transaction fees) you're willing to spend to get your NFT minted.  As my efforts today were experimental, I chose to set a "Custom" amount of GWEI for my first minting transaction, in an effort to save ETH while trading time. 

Referencing https://ethgasstation.info can help give an idea of what gas prices you may need to pay, but I found that, today at least, the prices on the Rainbow app were a little lower.  The good news about the options in Rainbow is that they tell you the going rate for your transaction, provide you the option to select the fastest gas (ie the one that will get your transaction minted as soon as possible, effectively putting your transaction as one of the top priorities on the blockchain), a middle of the road gas price, a slower/cheaper price, and/or the option to set your own "Custom" price. The app also makes it clear how much GWEI translates to how much ETH (or likely other crypto token) you have, so it's pretty easy to tell by how much your overall account balance is going to fall if you confirm the transaction at your selected gas price.

     Something I learned today when selecting a "Custom" price is that Rainbow and Rarible.com will deny the transaction if you set too low a gas (at least that's what happened to me today).  I welcomed that, because it meant that they were helping me choose a realistic "Custom" amount of gas, while also helping protect me from wasting my ETH in the case that gas prices were so high that miners would accept my gas incrementally for work completed even though the transaction may not have been completed further down the line, effectively meaning that I would lose the custom gas amount I had set while also not getting my NFT minted because I took too much risk up front by not offering closer to the going gas rate at the time I submitted my transaction.  

    I think cryptoadventure.org explains this last issue really well at Ethereum Gas - Everything You Need to Know About It (cryptoadventure.org); see "Ethereum Gas Limit and Gas Prices".

5.  Protect/remove your metadata.  I debated adding this first, but it isn't specific to Rarible.com or the Rainbow app.  Regardless, one of the benefits of minting NFTs is that there is a record of your digital product that is supposed to last.  With that said, it may be very difficult to know exactly what personal metadata you may be providing to someone else along with your creations when you upload them.  Because of this, it is a good idea to remove as much metadata from your content as possible before you agree to potentially sell it to an unknown buyer.  See An Overview of Image Metadata - How It Affects Web Performance and Security - KeyCDN for ways to do this.