1. Trim Guns
Air powered trim guns give much faster results which are also much neater and better. The wood doesn't split, you don't need to pre-drill and it leaves only small holes to fill. You can buy a variety of sizes but if your budget only allows you to get one then go for the most versatile choice which fires 5/8 to two inch 18 gauge brads. Once you have used a pneumatic gun you will find how easy it is to hold a moulding in exactly the right place with one hand while you instantly nail it in place with the other. The job then becomes very quick and easy.
Your tape measure is a vital piece of your equipment. Writing down measurements is a must. Use masking tape to stick the measurements on the side and then you won't forget any important sizes as you set up. Your tool box should also contain a range of marking gauges, carpenters pencils and marking knives, all designed to help you get the best results. Layout squares and combination squares make finding the centre of a board simple and accurate.
To get a perfect mitre talks practise. A disc sander is the ideal tool to shorten the work piece and angles can be adjusted by fractions of a degree. If you are preparing long mitres then it helps to add temporary triangular blocks and to use paper between the wood and the glue to prevent damage to the wood itself. Mitre guides can be clamped in place to give you the perfect length and angle. As you get more experienced you will be able to feel if the mitre lengths are exactly the same. They won't form a tight joint if they aren't!
4. Hammers and Pliers
Joiner's hammers are designed for all light woodwork assembly and general use. Look for heat treated and polished forged steel heads for durability. The hammer needs to be well balanced and made well enough to stand weight tolerance, crack testing and ideally fitted with an ash handle. Pliers are the handiest tool to keep in your pouch to aid with carpentry trim. They are also extremely useful for pulling nails from the back of the trim. There are a variety of types to choose from including slip joint with curved jaws or articulating axle, and long handled ones that exert pressure to close the jaws.
5. Whilst you are collecting your tools and generally building your experience you may find it useful to call a reputable handyman services. You can arrange a visit for a free evaluation so that would be very useful in planning your prices and your time and getting them to help you until you gain the confidence you need.