The link I posted earlier:
http://forum.mikrotik.com/t/forum-rules/173010/1
are the set of instructions to retrieve and post on the forum the export of your configuration (for review by other members).
The default firewall rules are usually just fine, but depending on the specific use of the device, they (or at least a part of them) might be either unneeded or (rare case) preventing something from working the way you need/want, if the use is just that of a “dumb” or “almost dumb” switch they shouldn’t be a problem.
Depending on the exact way/sequence you did the changes, the previous DHCP settings may have become sort of “orphaned”, (it can happen sort of pulling the rug from under someone’s feet) when this happens you will notice that some lines contains references to items starting with an asterisk, like *4 or *B, this is not a problem, it is only a way for RoS to show that something is not “right”, but it is better to check and remove those occurrences (if any), to have everything “clean”.
If the use is just that of a switch, you can remove all IP addresses (and then connect to the device via WInbox through MAC) or have anyway (as said much better/safer) a dedicated port for management out of the bridge with an IP address in a different network than the one you use.
Then - as always - the advice by rextended is sound, besides some added security, I would highlight particularly the importance of setting up properly NTP, so that when/if you need to access logs the entries will have correct date/time, not a 1970 date.
Unless you invite anav’s three friends (tom, dick and harry) 
http://forum.mikrotik.com/t/router-settings-from-beginners/177370/4
you shouldn’t need to overdo it with security provisions, that may backfire and become an obstacle in accessing the router/switch for management, sometimes too much of a good thing is just too much, I still believe that if “they” are after you, “they” can get you.