A tanto is a pretty simple project, so I say you should go for it. There are few rules, and most of them can be tweaked as you wish.
There have been many threads on tanto, and on habaki with good photos and tutorials. The custom search engine in the stickys will help find them.
A tanto can be aikuchi, or with tsuba. Most new makers make the mistake of making the tsuba way too big. Personally, I feel anything that sticks out over 1/4" is too large. Many I make have just a bare bump of a tsuba.
I like buffalo horn (black micarta or G-10 work as good substitutes). 3/16" thick is all the thickness a tanto tsuba needs ... and I feel 1/8" is just about right.
My opinion on a seppa on a tanto is it isn't necessary, and will create problems fitting the saya. If you use one, it must be the same size as the saya cap ,so it looks like a spacer when the blade is in the saya.
As John's photos show, a habaki in not necessary on a tanto. If you do build one, make it small and thin.
The blade grind can be traditional or a western double bevel. There is just a tad of sori, if any at all. I like about 1/8" to 1/4" sori ( tip to nakago-jiri) in a full size tanto.
The nakago/tang on a tanto can be a somewhat stubby hidden tang used with traditional two-piece tuska, or a more western huden tang in a one piece drilled out handle. I usually go with the full tang and traditional two-piece tsuka. On a tanto is actually closer to a 3/4 tang.. I grind down the sides of the tang an appropriate amount when wrapping with paracord or other maki. The kashira can be a cap of metal, buffalo horn, or just a hole you wrap through and around.
The underlayment for the wrap can be leather, or same' - stingray skin. On a tanto, there is no need for rawhide same' ( as is done for a katana/wakizashi tsuka), and the softer black and other colors of same' are fine. Menuki are also not needed. If used, they are small and thin. Coolest tanto menuki I ever saw was a post war, 10,000 yen note folded as an origami fish. When doing scales, a single stud through the handle with a small round emblem or other symbol screwed into each side is used as the menuki.
The kissaki on a classic tanto is not an abrupt angle. That is what I call an American tanto ( usually done with a double bevel).
The traditional tip is a gradual curve to a point. It shortest is should ever be is the width of the blade near the tip ( saki-haba). It can curve up anywhere from the last inch from the tip (Ko-kissaki), to a medium curve tip like a hunter ( Chu-kissaki), to something like a fillet knife ( O-kissaki), to a tip so long it ends at the middle of the blade ( Osaraku-tsukuri).
