Starting out, I bought the following tools to do slimline pens:
1. 7mm pen mill.
2. 7mm mandrel with #1 mt to match my lathe.
3. 7mm brad point drill bit.
4. Vise clamp for drilling blanks.
5. Small pin for inserting tubes into blanks.
6. Pen press.
7. Harbor Freight lathe chisels.
Items 4 and 6 are up for discussion in that you can come up with home made substitutes for those items. I decided to get the tools rather than try to make something homemade and not have it work (damhikt).I bought the 4 chisel set from HF to get a gouge that I didn't have and to regrind the skew into a scraper that I didn't have. Other lathe chisels I had inherited from my father. So far, I've been quite pleased with the HF chisels. They're doing everything I ask of them and take an edge quite well. They only cost about $10.00 a set.
I use polyurethane glue for the tubes going into the blanks. It has been recommended to me, to use epoxy for that purpose. It sets much faster. I'll probably go that route when I finish the bottle of poly glue.
Do a lot of reading on finishing. There are many different opinions on what works best. As a general statement the higher grit sandpaper you use the better. I use up to 2000 grit. Some recommend the micro mesh pads rated up to 12,000 for sanding. I now use two coats of ca glue, sanded between coats and a finial coat of gloss lacquer as a finish. Play around with it and see what pleases you the best.
Hope this helps.